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• Can GPU capabilities impact virtual machine performance?

  - by Dave White

  While this many not seem like a programming question directly, it impacts my development activities and so it seems like it belongs here. It seems that more and more developers are turning to virtual environments for development activities on their computers, SharePoint development being a prime example. Also, as a trainer, I have virtual training environments for all of the classes that I teach. I recently purchased a new Dell E6510 to travel around with. It has the i7 620M (Dual core, HyperThreaded cpu running at 2.66GHz) and 8 GB of memory. Reading the spec sheet, it sounded like it would be a great laptop to carry around and run virtual machines on. Getting the laptop though, I've been pretty disappointed with the user experience of developing in a virtual machine. Giving the Virtual Machine 4 GB of memory, it was slow and I could type complete sentences and watch the VM "catchup". My company has training laptops that we provide for our classes. They are Dell Precision M6400 Intel Core 2 Duo P8700 running at 2.54Ghz with 8 GB of memory and the experience on this laptops is night and day compared to the E6510. They are crisp and you barely aware that you are running in a virtual environment. Since the E6510 should be faster in all categories than the M6400, I couldn't understand why the new laptop was slower, so I did a component by component comparison and the only place where the E6510 is less performant than the M6400 is the graphics department. The M6400 is running a nVidia FX 2700m GPU and the E6510 is running a nVidia 3100M GPU. Looking at benchmarks of the two GPUs suggest that the FX 2700M is twice as fast as the 3100M. http://www.notebookcheck.net/Mobile-Graphics-Cards-Benchmark-List.844.0.html 3100M = 111th (E6510) FX 2700m = 47th (Precision M6400) Radeon HD 5870 = 8th (Alienware) The host OS is Windows 7 64bit as is the guest OS, running in Virtual Box 3.1.8 with Guest Additions installed on the guest. The IDE being used in the virtual environment is VS 2010 Premium. So after that long setup, my question is: Is the GPU significantly impacting the virtual machine's performance or are there other factors that I'm not looking at that I can use to boost the vm's performance? Do we now have to consider GPU performance when purchasing laptops where we expect to use virtualized development environments? Thanks in advance. Cheers, Dave

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• Thread.CurrentThread.CurrentUICulture not working consistently

  - by xTRUMANx

  I've been working on a pet project on the weekends to learn more about C# and have encountered an odd problem when working with localization. To be more specific, the problem I have is with System.Threading.Thread.CurrentThread.CurrentUICulture. I've set up my app so that the user can quickly change the language of the app by clicking a menu item. The menu item in turn, saves the two-letter code for the language (e.g. "en", "fr", etc.) in a user setting called 'Language' and then restarts the application. Properties.Settings.Default.Language = "en"; Properties.Settings.Default.Save(); Application.Restart(); When the application is started up, the first line of code in the Form's constructor (even before InitializeComponent()) fetches the Language string from the settings and sets the CurrentUICulture like so: public Form1() { Thread.CurrentThread.CurrentUICulture = new CultureInfo(Properties.Settings.Default.Language); InitializeComponent(); } The thing is, this doesn't work consistently. Sometimes, all works well and the application loads the correct language based on the string saved in the settings file. Other times, it doesn't, and the language remains the same after the application is restarted. At first I thought that I didn't save the language before restarting the application but that is definitely not the case. When the correct language fails to load, if I were to close the application and run it again, the correct language would come up correctly. So this implies that the Language string has been saved but the CurrentUICulture assignment in my form constructor is having no effect sometimes. Any help? Is there something I'm missing of how threading works in C#? This could be machine-specific, so if it makes any difference I'm using Pentium Dual-Core CPU. UPDATE Vlad asked me to check what the CurrentThread's CurrentUICulture is. So I added a MessageBox on my constructor to tell me what the CurrentUICulture two-letter code is as well as the value of my Language user string. MessageBox.Show(string.Format("Current Language: {0}\nCurrent UI Culture: {1}", Properties.Settings.Default.Language, Thread.CurrentThread.CurrentUICulture.TwoLetterISOLanguageName)); When the wrong language is loaded, both the Language string and CurrentUICulture have the wrong language. So I guess the CurrentUICulture has been cleared and my problem is actually with the Language Setting. So I guess the problem is that my application sometimes loads the previously saved language string rather than the last saved language string. If the app is restarted, it will then load the actual saved language string.

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• Python. How to iterate through a list of lists looking for a partial match

  - by Becca Millard

  I'm completely stuck on this, without even an idea about how to wrap my head around the logic of this. In the first half of the code, I have successfully generation a list of (thousands of) lists of players names and efficiency scores: eg name_order_list = [["Bob", "Farley", 12.345], ["Jack", "Donalds", 14.567], ["Jack", "Donalds", 13.421], ["Jack", "Donalds", 15.232],["Mike", "Patricks", 10.543]] What I'm trying to do, is come up with a way to make a list of lists of the average efficiency of each player. So in that example, Jack Donalds appears multiple times, so I'd want to recognize his name somehow and average out the efficiency scores. Then sort that new list by efficiency, rather than name. So then the outcome would be like: average_eff_list = [[12.345, "Bob", "Farley"], [14.407, "Jack", "Donalds"], [10.543, "Mike", "Patricks"]] Here's what I tried (it's kind of a mess, but should be readable): total_list = [] odd_lines = [name_order_list[i] for i in range(len(name_order_list)) if i % 2 == 0] even_lines = [name_order_list[i] for i in range(len(name_order_list)) if i % 2 == 1] i = 0 j = i-1 while i <= 10650: iteration = 2 total_eff = 0 while odd_lines[i][0:2] == even_lines[i][0:2]: if odd_lines[i][0:2] == even_lines[j][0:2]: if odd_lines[j][0:2] != even_lines[j][0:2]: total_eff = even_lines[j][2]/(iteration-1) iteration -= 1 #account fr the single (rather than dual) additional entry else: total_eff = total_eff if iteration == 2: total_eff = (odd_lines[i][2] + even_lines[i][2]) / iteration else: total_eff = ((total_eff * (iteration - 2)) + (odd_lines[i][2] + even_lines[i][2])) / iteration iteration += 2 i += 1 j += 1 if i > 10650: break else: if odd_lines[i][0:2] == even_lines[j][0:2]: if odd_lines[j][0:2] != even_lines[j][0:2]: total_eff = (odd_lines[i][2] + even_lines[j][2]) / iteration else: total_eff = ((total_eff * (iteration -2)) + odd_lines[i][2]) / (iteration - 1) if total_eff == 0: #there's no match at all total_odd = [odd_lines[i][2], odd_lines[i][0], odd_lines[i][1]] total_list.append(total_odd) if even_lines[i][0:2] != odd_lines[i+1][0:2]: total_even = [even_lines[i][2], even_lines[i][0], even_lines[i][1]] else: total = [total_eff, odd_lines[i][0], odd_lines[i][1]] total_list.append(total) i += 1 if i > 10650: break else: print(total_list) Now, this runs well enough (doesn't get stuck or print someone's name multiple times) but the efficiency values are off by a large amount, so I know that scores are getting missed somewhere. This is a problem with my logic, I think, so any help would be greatly appreciated. As would any advice about how to loop through that massive list in a smarter way, since I'm sure there is one... EIDT: for this exercise, I need to keep it all in a list format. I can make new lists, but no using dictionaries, classes, etc.

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• Copying metadata over a database link in Oracle 10g

  - by Tunde

  Thanks in advance for your help experts. I want to be able to copy over database objects from database A into database B with a procedure created on database B. I created a database link between the two and have tweaked the get_ddl function of the dbms_metadata to look like this: create or replace function GetDDL ( p_name in MetaDataPkg.t_string p_type in MetaDataPkg.t_string ) return MetaDataPkg.t_longstring is -- clob v_clob clob; -- array of long strings c_SYSPrefix constant char(4) := 'SYS_'; c_doublequote constant char(1) := '"'; v_longstrings metadatapkg.t_arraylongstring; v_schema metadatapkg.t_string; v_fullength pls_integer := 0; v_offset pls_integer := 0; v_length pls_integer := 0; begin SELECT DISTINCT OWNER INTO v_schema FROM all_objects@ENTORA where object_name = upper(p_name); -- get DDL v_clob := dbms_metadata.get_ddl(p_type, upper(p_name), upper(v_schema)); -- get CLOB length v_fullength := dbms_lob.GetLength(v_clob); for nIndex in 1..ceil(v_fullength / 32767) loop v_offset := v_length + 1; v_length := least(v_fullength - (nIndex - 1) * 32767, 32767); dbms_lob.read(v_clob, v_length, v_offset, v_longstrings(nIndex)); -- Remove table’s owner from DDL string: v_longstrings(nIndex) := replace( v_longstrings(nIndex), c_doublequote || user || c_doublequote || '.', '' ); -- Remove the following from DDL string: -- 1) "new line" characters (chr(10)) -- 2) leading and trailing spaces v_longstrings(nIndex) := ltrim(rtrim(replace(v_longstrings(nIndex), chr(10), ''))); end loop; -- close CLOB if (dbms_lob.isOpen(v_clob) > 0) then dbms_lob.close(v_clob); end if; return v_longstrings(1); end GetDDL; so as to remove the schema prefix that usually comes with metadata. I get a null value whenever I run this function over the database link with the following queries. select getddl( 'TABLE', 'TABLE1') from user_tables@ENTORA where table_name = 'TABLE1'; select getddl( 'TABLE', 'TABLE1') from dual@ENTORA; t_string is varchar2(30) t_longstring is varchar2(32767) and type t_ArrayLongString is table of t_longstring I would really appreciate it if any one could help. Many thanks.

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• How to stream semi-live audio over internet

  - by Thomas Tempelmann

  I want to write something like Skype, i.e. I have a constant audio stream on one computer and then recompress it in a format that's suitable for a latent internet connection, receive it on the other end and play it. Let's also assume that the internet connection is fairly modern and fast, i.e. DSL or alike, no slow connections over phone and such. The involved computers will also be rather modern (Dual Core Intel CPUs at 2GHz or more). I know how to handle the audio on the machines. What I don't know is how to transmit the audio in an efficient way. The challenges are: I'd like get good audio quality across the line. The stream should be received without drops. The stream may, however, be received with a little delay (a second delay is acceptable). I imagine that the transport software could first determine the average (and max) latency, then start the stream and tell the receiver to wait for that max latency before starting to play the audio. With that, if the latency doesn't get any higher, the entire stream will be playable on the other side without stutter or drops. If, due to unexpected IP latencies or blockages, the stream does get cut off, I want to be able to notice this so that I can take actions (e.g. abort the stream) and eventually start a new transmission. What are my options if I want do use ready-made software for the compression and tranmission? I have no intention to write my own audio compression engine, really. OTOH, I plan to sell the solution in a vertical market, meaning I can afford a few dollars of license fees per copy, but not $100s. I guess the simplest solution would be to just open a TCP stream, send a few packets back and forth to determine their running time (or even use UDP for that), then use the results as the guide for my max latency value, then simply fire the audio data in its raw form (uncompressed 16 bit stereo), along with a timing code over the TCP connection. The receiver reads the data and plays it with the pre-determined delay. That might just work with the type of fast connection I expect. I just wonder if there are better solutions to reach this goal, with better performance (lower latency) and less data (compressed). BTW, I first try to implement this on OS X, but might want to do it on Windows, too, if it proves successful.

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• Is there a way to split a widescreen monitor in to two or more virtual monitors?

  - by Mike Thompson

  Like most developers I have grown to love dual monitors. I won't go into all the reasons for their goodness; just take it as a given. However, they are not perfect. You can never seem to line them up "just right". You always end up with the monitors at slight funny angles. And of course the bezel always gets in the way. And this is with identical monitors. The problem is much worse with different monitors -- VMWare's multi monitor feature won't even work with monitors of differnt resolutions. When you use multiple monnitors, one of them becomes your primary monitor of focus. Your focus may flip from one monitor to the other, but at any point in time you are usually focusing on only one monitor. There are exceptions to this (WinDiff, Excel), but this is generally the case. I suggest that having a single large monitor with all the benefits of multiple smaller monitors would be a better solution. Wide screen monitors are fantastic, but it is hard to use all the space efficiently. If you are writing code you are generally working on the left-hand side of the window. If you maximize an editor on a wide-screen monitor the right-hand side of the window will be a sea of white. Programs like WinSplit Revolution will help to organise your windows, but this is really just addressing the symptom, not the problem. Even with WinSplit Revolution, when you maximise a window it will take up the whole screen. You can't lock a window into a specific section of the screen. This is where virtual monitors comes in. What would be really nice is a video driver that sits on top of the existing driver, but allows a single monitor to be virtualised into multiple monitors. Control Panel would see your single physical monitor as two or more virtual monitors. The software could even support a virtual bezel to emphasise what is happening, or you could opt for seamless mode. Programs like WinSplit Revolution and UltraMon would still work. This virtual video driver would allow you to slice & dice your physical monitor into as many virtual monitors as you want. Does anybody know if such software exists? If not, are there any budding Windows display driver guru's out there willing to take up the challenge? I am not after the myriad of virtual desktop/window manager programs that are available. I get frustrated with these programs. They seem good at first but they usually have some strange behaviour and don't work well with other programs (such as WinSplit Revolution). I want the real thing!

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• Across process marhalling problem with an array of points

  - by ElMagn

  Hi All, We have what we think is a marshalling problem with a renderer object when called across process boundaries. The renderer is an ATL COM server with a COM object that implements the IPoints interface defined below: typedef [uuid(B0E01719-005A-427c-B9DD-B42A18E969AE)] struct Point { double X; double Y; } Point; [ object, uuid(3BFECFE3-B4FB-4f14-8257-6E065D02E3B3), helpstring("IPoints Interface"), dual, ] interface IPoints : IDispatch { HRESULT DrawPolyLine([in] long hDC, [in] short count, [in, size_is(count)] Point * points ); // many more like DrawLine } The count parameter represents the number of points and the points parameter represents an array of the actual points. We have two process running, a graphical display process (GDP) and a tabular (grid) display process (TDP). A factory in the GDP, written in C#, creates the renderer and the clients of the renderer in the GDP. When the clients call into the renderer, everything displays correctly. The renderer is created at start up BTW. There is another factory in the TDP, written in VB6, that calls into the factory in the GDP to create the clients. When the clients call into the renderer, only the first point in the array is marshaled correctly, all the other points are garbage. Seems that the rendering works only when the client creation is started from the same process as the renderer. Now, i am not sure what the solution to this problem is. It seems that if we can guarantee that the clients are always created from a thread in the same GDP process as the renderer then the points are marshaled correctly. We tried using a background thread from the Thread Pool in C# and it indeed worked. The problem is that Windows Forms created from the clients stopped working because accessing the form's controls from a thread other than the thread that created the control is not allowed. We might change the calls to access the forms but we have quite a few of them and are trying to look into a different solution that might involve making changes to the renderer. The other problem is that the renderer is legacy code and we can't just change the interface. I am wondering what can we do to the renderer's interface that would help with marshalling from across process calls. Any ideas would be greatly appreciated. Regards, ElMagn

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• Stored procedure performance randomly plummets; trivial ALTER fixes it. Why?

  - by gWiz

  I have a couple of stored procedures on SQL Server 2005 that I've noticed will suddenly take a significantly long time to complete when invoked from my ASP.NET MVC app running in an IIS6 web farm of four servers. Normal, expected completion time is less than a second; unexpected anomalous completion time is 25-45 seconds. The problem doesn't seem to ever correct itself. However, if I ALTER the stored procedure (even if I don't change anything in the procedure, except to perhaps add a space to the script created by SSMS Modify command), the completion time reverts to expected completion time. IIS and SQL Server are running on separate boxes, both running Windows Server 2003 R2 Enterprise Edition. SQL Server is Standard Edition. All machines have dual Xeon E5450 3GHz CPUs and 4GB RAM. SQL Server is accessed using its TCP/IP protocol over gigabit ethernet (not sure what physical medium). The problem is present from all web servers in the web farm. When I invoke the procedure from a query window in SSMS on my development machine, the procedure completes in normal time. This is strange because I was under the impression that SSMS used the same SqlClient driver as in .NET. When I point my development instance of the web app to the production database, I again get the anomalous long completion time. If my SqlCommand Timeout is too short, I get System.Data.SqlClient.SqlException: Timeout expired. The timeout period elapsed prior to completion of the operation or the server is not responding. Question: Why would performing ALTER on the stored procedure, without actually changing anything in it, restore the completion time to less than a second, as expected? Edit: To clarify, when the procedure is running slow for the app, it simultaneously runs fine in SSMS with the same parameters. The only difference I can discern is login credentials (next time I notice the behavior, I'll be checking from SSMS with the same creds). The ultimate goal is to get the procs to sustainably run with expected speed without requiring occasional intervention. Resolution: I wanted to to update this question in case others are experiencing this issue. Following the leads of the answers below, I was able to consistently reproduce this behavior. In order to test, I utilize sp_recompile and pass it one of the susceptible sprocs. I then initiate a website request from my browser that will invoke the sproc with atypical parameters. Lastly, I initiate a website request to a page that invokes the sproc with typical parameters, and observe that the request does not complete because of a SQL timeout on the sproc invocation. To resolve this on SQL Server 2005, I've added OPTIMIZE FOR hints to my SELECT. The sprocs that were vulnerable all have the "all-in-one" pattern described in this article. This pattern is certainly not ideal but was a necessary trade-off given the timeframe for the project.

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• Is a Multi-DAL Approach the way to go here?

  - by Krisc

  Working on the data access / model layer in this little MVC2 project and trying to think things out to future projects. I have a database with some basic tables and I have classes in the model layer that represent them. I obviously need something to connect the two. The easiest is to provide some sort of 'provider' that can run operations on the database and return objects. But this is for a website that would potentially be used "a lot" (I know, very general) so I want to cache results from the data layer and keep the cache updated as new data is generated. This question deals with how best to approach this problem of dual DALS. One that returns cached data when possible and goes to the data layer when there is a cache miss. But more importantly, how to integrate the core provider (thing that goes into database) with the caching layer so that it too can rely on cached objects rather than creating new ones. Right now I have the following interfaces: IDataProvider is used to reach the database. It doesn't concern itself with the meaning of the objects it produces, but simply the way to produce them. interface IDataProvider{ // Select, Update, Create, et cetera access IEnumerable<Entry> GetEntries(); Entry GetEntryById(int id); } IDataManager is a layer that sits on top of the IDataProvider layer and manages the cache interface IDataManager : IDataProvider{ void ClearCache(); } Note that in practice the IDataManager implementation will have useful helper functions to add objects to their related cache stores. (In the future I may define other functions on the interface) I guess what I am looking for is the best way to approach a loop back from the IDataProvider implementations so that they can access the cache. Or a different approach entirely may be in order? I am not very interested in 3rd party products at the moment as I am interested in the design of these things much more than this specific implementation. Edit: I realize the title may be a bit misleading. I apologize for that... not sure what to call this question.

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• C++ Vector vs Array (Time)

  - by vsha041

  I have got here two programs with me, both are doing exactly the same task. They are just setting an boolean array / vector to the value true. The program using vector takes 27 seconds to run whereas the program involving array with 5 times greater size takes less than 1 s. I would like to know the exact reason as to why there is such a major difference ? Are vectors really that inefficient ? Program using vectors #include <iostream> #include <vector> #include <ctime> using namespace std; int main(){ const int size = 2000; time_t start, end; time(&start); vector<bool> v(size); for(int i = 0; i < size; i++){ for(int j = 0; j < size; j++){ v[i] = true; } } time(&end); cout<<difftime(end, start)<<" seconds."<<endl; } Runtime - 27 seconds Program using Array #include <iostream> #include <ctime> using namespace std; int main(){ const int size = 10000; // 5 times more size time_t start, end; time(&start); bool v[size]; for(int i = 0; i < size; i++){ for(int j = 0; j < size; j++){ v[i] = true; } } time(&end); cout<<difftime(end, start)<<" seconds."<<endl; } Runtime - < 1 seconds Platform - Visual Studio 2008 OS - Windows Vista 32 bit SP 1 Processor Intel(R) Pentium(R) Dual CPU T2370 @ 1.73GHz Memory (RAM) 1.00 GB Thanks Amare

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• VB.Net 2008 IDE hanging - MSVB7.dll eating 100% CPU when editing code

  - by Andrew Backer

  I am having a problem with msvb7.dll eating 50%+ cpu on my dual core system. This usually lasts 10-30 seconds or so, during which time the IDE is non-responsive. This occurs when I do pretty much anything in the text editor, and can be replicated by simply adding blank lines to a function, and then deleting them. Or pasting some code. Or... lotsa stuff. SP1 installed I had DevExpress' refactor/coderush, components, and codeit.right installed, but have removed all 3 of them. (I had installed the latest version of Refactor Pro! (9.3.4), perhaps the day before) I have tried a VS.NET Repair. There is a kb that referenced some cpu destroying with vb, but it was included in SP1 Also: The solution consists of ~30 VB projects and 2 C# projects 8 other developers aren't having any issues with this (or at least not the SAME issues, we all have em) Clean get from TFS was done Project builds properly, can can even debug. This doesn't seem to happen on really small solutions, but perhaps it does and it just goes away super quick. Any clues at all as to what might be causing this, or how to fix it? I REALLY don't want to lose another day uninstalling and reinstalling and patching and so on =) If that even fixes it. Here is the stack trace (process explorer) that I get from the threads window when the msvb7.dll is churning. --- title in process explorer [threads] tab for process -------- cpu:49.28% cswitch delta: 300 to 3500 startaddress: [msvb7.dll+0x4218c] msvb7.dll version: 9.0.30729.1 --- actual stack trace ------- ntkrnlpa.exe!KiUnexpectedInterrupt+0x121 ntkrnlpa.exe!ZwYieldExecution+0x1c56 ntkrnlpa.exe!KiDispatchInterrupt+0x72e NDIS.sys!NdisFreeToBlockPool+0x15e1 // shortened stack trace. all of these are from msvb7, msvb7.dll+0x46ce7 <- 0x2676a <- 0x2698e <- 0x38031 <- 0x2659f <- 0x26644 msvb7.dll+0x25f29 <- 0x2ac7a <- 0x27522 <- 0x274a0 <- 0x2b5ce <- 0x2b6e4 msvb7.dll+0x67d0a <- 0x68551 <- 0x6817b <- 0x681f0 <- 0x67c38 <- 0x65fa8 msvb7.dll+0x666c6 <- 0x6672c <- 0x6673d <- 0x6677c <- 0x667b4 <- 0x63c77 msvb7.dll+0x63e97 <- 0x42c3a <- 0x42bc1 <- 0x41bd7 kernel32.dll!GetModuleFileNameA+0x1b4 This is the list of stuff from "copy info" in help-about, shortened to a resonable length. Microsoft Visual Studio 2008 | Version 9.0.30729.1 SP Microsoft Visual Studio 2008 Professional Edition - ENU Service Pack 1 (KB945140) KB945140 Microsoft .NET Framework | Version 3.5 SP1 Microsoft Visual Basic 2008 Microsoft Visual C# 2008 Microsoft Visual F# for Visual Studio 2008 Microsoft Visual Studio 2008 Team Explorer | Version 9.0.30729.1 Microsoft Visual Studio 2008 Tools for Office Microsoft Visual Web Developer 2008 Hotfix for Microsoft Visual Studio 2008 Professional Edition - ENU KB944899, KB945282, KB946040, KB946308, KB946344, KB946581, KB947171 KB947173, KB947180, KB947540, KB947789, KB948127, KB946260, KB946458, KB948816 Microsoft Recipe Framework Package 8.0 Process Editor WIT Designer 1.4.0.0 Process Editor for Microsoft Visual Studio Team Foundation Server, Version 1.4.0.0 tangible T4 Editor 9.0 tangible T4 Text Template Editor - T4 Editor tangibleprojectsystem 1.0 Team Foundation Server Power Tools October 2008 SQL Prompt 4.0 (disabled)

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• Determining cause of high NFS/IO utilization without iotop

  - by Matt

  I have a server that is doing an NFSv4 export for user's home directories. There are roughly 25 users (mostly developers/analysts) and about 40 servers mounting the home directory export. Performance is miserable, with users often seeing multi-second lags for simple commands (like ls, or writing a small text file). Sometimes the home directory mount completely hangs for minutes, with users getting "permission denied" errors. The hardware is a Dell R510 with dual E5620 CPUs and 8 GB RAM. There are eight 15k 2.5” 600 GB drives (Seagate ST3600057SS) configured in hardware RAID-6 with a single hot spare. RAID controller is a Dell PERC H700 w/512MB cache (Linux sees this as a LSI MegaSAS 9260). OS is CentOS 5.6, home directory partition is ext3, with options “rw,data=journal,usrquota”. I have the HW RAID configured to present two virtual disks to the OS: /dev/sda for the OS (boot, root and swap partitions), and /dev/sdb for the home directories. What I find curious, and suspicious, is that the sda device often has very high utilization, even though it only contains the OS. I would expect this virtual drive to be idle almost all the time. The system is not swapping, according to "free" and "vmstat". Why would there be major load on this device? Here is a 30-second snapshot from iostat: Time: 09:37:28 AM Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0.00 44.09 0.03 107.76 0.13 607.40 11.27 0.89 8.27 7.27 78.35 sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 sda2 0.00 44.09 0.03 107.76 0.13 607.40 11.27 0.89 8.27 7.27 78.35 sdb 0.00 2616.53 0.67 157.88 2.80 11098.83 140.04 8.57 54.08 4.21 66.68 sdb1 0.00 2616.53 0.67 157.88 2.80 11098.83 140.04 8.57 54.08 4.21 66.68 dm-0 0.00 0.00 0.03 151.82 0.13 607.26 8.00 1.25 8.23 5.16 78.35 dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 dm-2 0.00 0.00 0.67 2774.84 2.80 11099.37 8.00 474.30 170.89 0.24 66.84 dm-3 0.00 0.00 0.67 2774.84 2.80 11099.37 8.00 474.30 170.89 0.24 66.84 Looks like iotop is the ideal tool to use to sniff out these kinds of issues. But I'm on CentOS 5.6, which doesn't have a new enough kernel to support that program. I looked at Determining which process is causing heavy disk I/O?, and besides iotop, one of the suggestions said to do a "echo 1 /proc/sys/vm/block_dump". I did that (after directing kernel messages to tempfs). In about 13 minutes I had about 700k reads or writes, roughly half from kjournald and the other half from nfsd: # egrep " kernel: .*(READ|WRITE)" messages | wc -l 768439 # egrep " kernel: kjournald.*(READ|WRITE)" messages | wc -l 403615 # egrep " kernel: nfsd.*(READ|WRITE)" messages | wc -l 314028 For what it's worth, for the last hour, utilization has constantly been over 90% for the home directory drive. My 30-second iostat keeps showing output like this: Time: 09:36:30 PM Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await svctm %util sda 0.00 6.46 0.20 11.33 0.80 71.71 12.58 0.24 20.53 14.37 16.56 sda1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 sda2 0.00 6.46 0.20 11.33 0.80 71.71 12.58 0.24 20.53 14.37 16.56 sdb 137.29 7.00 549.92 3.80 22817.19 43.19 82.57 3.02 5.45 1.74 96.32 sdb1 137.29 7.00 549.92 3.80 22817.19 43.19 82.57 3.02 5.45 1.74 96.32 dm-0 0.00 0.00 0.20 17.76 0.80 71.04 8.00 0.38 21.21 9.22 16.57 dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 dm-2 0.00 0.00 687.47 10.80 22817.19 43.19 65.48 4.62 6.61 1.43 99.81 dm-3 0.00 0.00 687.47 10.80 22817.19 43.19 65.48 4.62 6.61 1.43 99.82

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• Xen kernel can't see 2 disks of 6 of 1TB, does it have a limitation?

  - by PartySoft

  Linux gentoo-xen 2.6.18-xen-r12 #3 SMP Tue Oct 5 09:28:53 PDT 2010 x86_64 Intel(R) Xeon(R) CPU E5506 @ 2.13GHz GenuineIntel GNU/Linux I have 6 disks of 1 TB and i can't see all of them only 4, can anyone give me an ideea what can i do ? Filesystem Size Used Avail Use% Mounted on rootfs 886G 4.4G 836G 1% / /dev/sda3 886G 4.4G 836G 1% / rc-svcdir 1.0M 44K 980K 5% /lib64/rc/init.d shm 7.9G 0 7.9G 0% /dev/shm /dev/sdb1 917G 200M 871G 1% /home2 /dev/sdc1 917G 200M 871G 1% /home3 /dev/sdd1 917G 200M 871G 1% /home4 The hardware is Dual xeon E5506 processors on a supermicro X8DTL mobo 4.346585] ata3.00: ATA-8, max UDMA/133, 1953525168 sectors: LBA48 NCQ (depth 0/32) [ 4.346588] ata3.00: ata3: dev 0 multi count 16 [ 4.352861] ata3.00: configured for UDMA/133 [ 4.352867] scsi3 : ata_piix [ 4.352875] PM: Adding info for No Bus:host3 [ 4.510584] ata4.00: ATA-8, max UDMA/133, 1953525168 sectors: LBA48 NCQ (depth 0/32) [ 4.510587] ata4.00: ata4: dev 0 multi count 16 [ 4.516848] ata4.00: configured for UDMA/133 [ 4.516861] PM: Adding info for No Bus:target2:0:0 [ 4.516905] Vendor: ATA Model: SAMSUNG HD103SJ Rev: 1AJ1 [ 4.516910] Type: Direct-Access ANSI SCSI revision: 05 [ 4.516920] PM: Adding info for scsi:2:0:0:0 [ 4.517452] SCSI device sde: 1953525168 512-byte hdwr sectors (1000205 MB) [ 4.517460] sde: Write Protect is off [ 4.517461] sde: Mode Sense: 00 3a 00 00 [ 4.517478] SCSI device sde: drive cache: write back [ 4.517514] SCSI device sde: 1953525168 512-byte hdwr sectors (1000205 MB) [ 4.517521] sde: Write Protect is off [ 4.517522] sde: Mode Sense: 00 3a 00 00 [ 4.517532] SCSI device sde: drive cache: write back [ 4.517534] sde: sde1 [ 4.524551] sd 2:0:0:0: Attached scsi disk sde [ 4.524855] sd 2:0:0:0: Attached scsi generic sg4 type 0 [ 4.524874] PM: Adding info for No Bus:target3:0:0 [ 4.524928] Vendor: ATA Model: SAMSUNG HD103SJ Rev: 1AJ1 [ 4.524933] Type: Direct-Access ANSI SCSI revision: 05 [ 4.524946] PM: Adding info for scsi:3:0:0:0 [ 4.525216] SCSI device sdf: 1953525168 512-byte hdwr sectors (1000205 MB) [ 4.525227] sdf: Write Protect is off [ 4.525228] sdf: Mode Sense: 00 3a 00 00 [ 4.525242] SCSI device sdf: drive cache: write back [ 4.525280] SCSI device sdf: 1953525168 512-byte hdwr sectors (1000205 MB) [ 4.525286] sdf: Write Protect is off [ 4.525289] sdf: Mode Sense: 00 3a 00 00 [ 4.525301] SCSI device sdf: drive cache: write back [ 4.525302] sdf: sdf1 [ 4.532691] sd 3:0:0:0: Attached scsi disk sdf [ 4.533010] sd 3:0:0:0: Attached scsi generic sg5 type 0 [ 4.977669] scsi: <fdomain> Detection failed (no card) [ 5.030479] GDT-HA: Storage RAID Controller Driver. Version: 3.05 [ 5.030635] GDT-HA: Found 0 PCI Storage RAID Controllers [ 5.372350] Fusion MPT base driver 3.04.01 [ 5.372358] Copyright (c) 1999-2005 LSI Logic Corporation [ 5.579176] Fusion MPT SPI Host driver 3.04.01 [ 5.881777] ieee1394: Initialized config rom entry `ip1394' [ 6.166745] ieee1394: sbp2: Driver forced to serialize I/O (serialize_io=1) [ 6.166748] ieee1394: sbp2: Try serialize_io=0 for better performance [ 6.428866] md: md driver 0.90.3 MAX_MD_DEVS=256, MD_SB_DISKS=27 [ 6.428872] md: bitmap version 4.39 [ 6.431518] md: raid0 personality registered for level 0 [ 6.495979] md: raid1 personality registered for level 1 [ 6.570270] raid5: automatically using best checksumming function: generic_sse [ 6.575523] generic_sse: 6608.000 MB/sec [ 6.575526] raid5: using function: generic_sse (6608.000 MB/sec) [ 6.596226] raid6: int64x1 1835 MB/s [ 6.613231] raid6: int64x2 1773 MB/s [ 6.630256] raid6: int64x4 1675 MB/s [ 6.647296] raid6: int64x8 1027 MB/s [ 6.664267] raid6: sse2x1 3578 MB/s [ 6.681268] raid6: sse2x2 4207 MB/s [ 6.698280] raid6: sse2x4 4625 MB/s [ 6.698281] raid6: using algorithm sse2x4 (4625 MB/s) [ 6.698285] md: raid6 personality registered for level 6 [ 6.698286] md: raid5 personality registered for level 5 [ 6.698288] md: raid4 personality registered for level 4 [ 6.781090] md: raid10 personality registered for level 10 [ 7.007043] Intel(R) PRO/1000 Network Driver - version 7.1.9-k4 [ 7.007046] Copyright (c) 1999-2006 Intel Corporation. [ 9.229465] kjournald starting. Commit interval 5 seconds [ 9.229476] EXT3-fs: mounted filesystem with ordered data mode.

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• Kernel panic when bringing up DRBD resource

  - by sc.

  I'm trying to set up two machines synchonizing with DRBD. The storage is setup as follows: PV - LVM - DRBD - CLVM - GFS2. DRBD is set up in dual primary mode. The first server is set up and running fine in primary mode. The drives on the first server have data on them. I've set up the second server and I'm trying to bring up the DRBD resources. I created all the base LVM's to match the first server. After initializing the resources with `` drbdadm create-md storage I'm bringing up the resources by issuing drbdadm up storage After issuing that command, I get a kernel panic and the server reboots in 30 seconds. Here's a screen capture. My configuration is as follows: OS: CentOS 6 uname -a Linux host.structuralcomponents.net 2.6.32-279.5.2.el6.x86_64 #1 SMP Fri Aug 24 01:07:11 UTC 2012 x86_64 x86_64 x86_64 GNU/Linux rpm -qa | grep drbd kmod-drbd84-8.4.1-2.el6.elrepo.x86_64 drbd84-utils-8.4.1-2.el6.elrepo.x86_64 cat /etc/drbd.d/global_common.conf global { usage-count yes; # minor-count dialog-refresh disable-ip-verification } common { handlers { pri-on-incon-degr "/usr/lib/drbd/notify-pri-on-incon-degr.sh; /usr/lib/drbd/notify-emergency-reboot.sh; echo b /proc/sysrq-trigger ; reboot -f"; pri-lost-after-sb "/usr/lib/drbd/notify-pri-lost-after-sb.sh; /usr/lib/drbd/notify-emergency-reboot.sh; echo b /proc/sysrq-trigger ; reboot -f"; local-io-error "/usr/lib/drbd/notify-io-error.sh; /usr/lib/drbd/notify-emergency-shutdown.sh; echo o /proc/sysrq-trigger ; halt -f"; # fence-peer "/usr/lib/drbd/crm-fence-peer.sh"; # split-brain "/usr/lib/drbd/notify-split-brain.sh root"; # out-of-sync "/usr/lib/drbd/notify-out-of-sync.sh root"; # before-resync-target "/usr/lib/drbd/snapshot-resync-target-lvm.sh -p 15 -- -c 16k"; # after-resync-target /usr/lib/drbd/unsnapshot-resync-target-lvm.sh; } startup { # wfc-timeout degr-wfc-timeout outdated-wfc-timeout wait-after-sb become-primary-on both; wfc-timeout 30; degr-wfc-timeout 10; outdated-wfc-timeout 10; } options { # cpu-mask on-no-data-accessible } disk { # size max-bio-bvecs on-io-error fencing disk-barrier disk-flushes # disk-drain md-flushes resync-rate resync-after al-extents # c-plan-ahead c-delay-target c-fill-target c-max-rate # c-min-rate disk-timeout } net { # protocol timeout max-epoch-size max-buffers unplug-watermark # connect-int ping-int sndbuf-size rcvbuf-size ko-count # allow-two-primaries cram-hmac-alg shared-secret after-sb-0pri # after-sb-1pri after-sb-2pri always-asbp rr-conflict # ping-timeout data-integrity-alg tcp-cork on-congestion # congestion-fill congestion-extents csums-alg verify-alg # use-rle protocol C; allow-two-primaries yes; after-sb-0pri discard-zero-changes; after-sb-1pri discard-secondary; after-sb-2pri disconnect; } } cat /etc/drbd.d/storage.res resource storage { device /dev/drbd0; meta-disk internal; on host.structuralcomponents.net { address 10.10.1.120:7788; disk /dev/vg_storage/lv_storage; } on host2.structuralcomponents.net { address 10.10.1.121:7788; disk /dev/vg_storage/lv_storage; } /var/log/messages is not logging anything about the crash. I've been trying to find a cause of this but I've come up with nothing. Can anyone help me out? Thanks.

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• How to diagnose computer lockup/freezing problem

  - by Scott Mitchell

  I built a desktop computer a couple years back with the following specs: CPU: Intel Core 2 Quad Q9300 Yorkfield 2.5GHz 6MB L2 Cache LGA 775 95W Quad-Core Processor BX80580Q9300 Motherboard: EVGA 122-CK-NF68-T1 LGA 775 NVIDIA nForce 680i SLI ATX Intel Motherboard Video Card: Two EVGA 256-P2-N758-TR GeForce 8600GT SCC 256MB 128-bit GDDR3 PCI Express x16 SLI Supported Video Card PSU: SeaSonic S12 Energy Plus SS-550HT 550W ATX12V V2.3 / EPS12V V2.91 SLI Certified CrossFire Ready 80 PLUS Certified Active PFC Power Supply Memory: Two G.SKILL 4GB (2 x 2GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model F2-6400CL5D-4GBPQ Since its inception, the machine has periodically locked up, the regularlity having varied over the years from once a day to once a month. Typically, lockups happen once every few days. By "lockup" I mean my computer just freezes. The screen locks up, I can't move the mouse. Hitting keys on my keyboard that normally turn LEDs on or off on the keyboard (such as Caps Lock) no longer turn the LEDs on or off. If there was music playing at the time of the lockup, noise keeps coming out of the speakers, but it's just the current frequency/note that plays indefinitely. There is no BSOD. When such a lockup occurs I have to do a hard reboot by either turning off the computer or hitting the reset button. I have the most recent version of the NVIDIA hardware drivers, and update them semi-regularly, but that hasn't seemed to help. I am currently using Windows 7 x64, but was previously using Windows Server 2003 x64 and having the same lockup issues. My guess is that it's somehow video driver or motherboard related, but I don't know how to go about diagnosing this problem to narrow down which of the two is the culprit. Additional information re: cooling Regarding cooling... I've not installed any after-market cooling systems aside from two regular fans I scavenged from an older computer. The fan atop the CPU is the one that shipped with it. One of the two scavenged fans I added it located at the bottom tower of the corner, in an attempt to create some airflow from front to back. The second fan is pointed directly at the two video cards. SpeedFan installation and readings Per studiohack's suggestion, I installed SpeedFan, which provided the following temperature readings: GPU: 63C GPU: 65C System: 76C CPU: 64C AUX: 36C Core 0: 78C Core 1: 76C Core 2: 79C Core 3: 79C Update #3: Another Lockup :-( Well, I had another lockup last night. :-( SpeedFan reported the CPU temp at 38 C when it happened, and there was no spike in temperature leading up to the freeze. One thing I notice is that the freeze seems more likely to happen if I am watching a video. In fact, of the last 5 freezes over the past month, 4 of them have been while watching a video on Flickr. Not necessarily the same video, but a video nevertheless. I don't know if this is just coincidence or if it means anything. (As an aside, each night before bedtime my 2 year old daughter sits on my lap and watches some home videos on Flickr and, in the last month, has learned the phrase, "Uh oh, computer broke.") Update #4: MemTest86 and 3DMark06 Test Results: Per suggestions in the comments, I ran the MemTest86 overnight and it cycled through the 8 GB of memory 5 times without error. I also ran the 3DMark06 test without a problem (see my scores at http://3dmark.com/3dm06/15163549). So... what now? :-) Any further suggestions on what to check? Is there some way to get a stack trace or something when the computer locks like that? Thanks

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• Random Slow Response

  - by ARehman

  We have an ASP.NET MVC 1.0 application running on Windows Server 2008 – Standard (32 –bit), Dual Core Xeon (3.0 GHz), 2 G.B R.A.M. Most of the times application renders response in 3-4 seconds, but sometimes users get very late response and delay is up to 40 seconds or more than a minute. It happens in following way: User browsed a page, idle for 5, 10 or 15 minutes, tried to browse same page or some other. Now, there is a chance that he will see late response whereas the app pool is still up and running. This can happen with any arbitrary page. We have tried followings/observations. Moved the application to stand alone web server App Pool idle shutdown time is 60 minutes. There are no abrupt shut downs/restarts. CPU or memory doesn’t spike. No delays in SQL queries. Modified App Pool setting to run in classic-mode. It didn’t help. Plugged-in custom module to log all those requests which took more than 5 seconds to complete. It didn’t pick any request of interest. Enabled ‘Failed Request Tracing’ to log all those requests which take 20 or more seconds to complete. It didn’t log anything. Event Viewer, HTTPER log, W3SVC logs or WAS logs don’t indicate anything. HTTPERR only has ‘_ _ Timer_ConnectionIdle _ _’ entries. There is not much traffic to server. This can happen also if only two users are active. Next we captured TCP/IP terrific on both a user and server end with Wireshark and below are details in brief of this slowness: Browser sends a request for ~/User/Home/ (GET Request) by setting up a receiving end point using port 'wlbs(port-2504)'. I'm not sure if this could be a problem in some way that browser didn't hand-shake with the server first and assumed that last connection is still open, whereas, I browsed the same page 4 minutes ago and didn't perform any activity with site after that. If I see the HTTPERR log, it indicates that it has ‘_ _ Timer_ConnectionIdle _ _ _’ entry for my last activity with server. Browser (I was using Chrome) waits for any response from the server, doesn’t find any then starts retransmitting the same request using same end point after incrementing wait intervals, e.g. after 8, 18, 29, 40, 62, and 92 seconds. All these GET requests were received by server as well. But, server didn’t send any packet to client. Browser didn't see any response on the end point it set up in point 1, it opened a new end point 'optiwave-lm (port-2524)', did a hand shake with the server and transmitted the same request again. Server received, processed it, and returned successful response. What happened to earlier 6-7 requests? Whether they were passed on to HTTP.SYS or not? Why Failed Request Tracing not logged anything, we didn't find any clue yet. Server served the same page successfully just 4 minutes ago. Looking forward for more suggestions/solutions. -- Thanks

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• What would make a noise in a PC on graphics operations on a passively-cooled system?

  - by T.J. Crowder

  I have this system based on the Intel D510MO motherboard, which is basically an Atom D510 (dual-core HT Atom w/built-in GPU), an Intel NM10 chipset, and a Realtek Gigabit LAN controller. It's entirely passively cooled. I noticed almost immediately that there was a kind of very, very soft noise that corresponded with graphics operations, sort of the noise you'd get if you had a sheet of flat paper and slid something really light across it — but more electronic than that. I wrote it off as observation error and/or disk activity triggered by the graphics operation (although the latter seemed like a lot of unnecessary disk activity). It isn't. I got curious enough that I finally did a few controlled experiments, and here's what I've determined: It isn't the HDD. For one thing, the sounds the HDD makes (when seeking, when reading or writing, when just sitting there spinning) is different. For another, I used sudo hdparm -y /dev/sda (I'm using Ubuntu 10.04 LTS) to temporarily put the disk on standby while making sure that non-disk graphics op was happening in a loop. The disk spun down, but the other sound continued, corresponding perfectly with the timing of the graphics op. (Then the disk spun up again, but it takes long enough that I could rule out the HDD.) It isn't the monitor; I ensured the two were well physically-separated and the sound was definitely coming from the main box. It isn't something else in the room; the sound is coming from the box. It isn't cross-talk to an audio circuit coming out the speakers. (It doesn't have any speakers.) It isn't my mouse (e.g., when I'm trying to make graphics ops happen); the sound happens if I set up a recurring operation and don't use the mouse at all, or if I lift the mouse off the table slightly (but enough that the laser still registers movement). It isn't the voices in my head; they never whisper like that. Other observations: It doesn't seem to matter what the graphics operation is; anything that changes what's on the screen seems to do it. I get the sound when moving the mouse over the Chromium tab bar (which makes the tab backgrounds change); I get it when a web page has a counter on it that changes the text on the page: I get it when dragging window contents around. The sound is very, very slightly louder if the graphics op is larger, like scrolling a text area when writing a question on superuser.com, than for smaller operations like the tick counter on the web page. But it's very slight. It's fairly loud (and of good duration) when the op involves color changes to substantial surface areas. For instance, when asking a question here on superuser and you move the cursor between the question box and the tag box, and the help to the right fades out, changes, and fades back in. (Yet another example related to the web browser, so let me say: I hear it when operations completely unrelated to the web browser as well.) It doesn't sound like arcing or anything like that (I'd've shut off the machine Right Quick Like if it did). Moving windows does it. Scrolling windows (by and large) doesn't. I have the feeling I've heard this sort of thing before, when all system fans were on low and such, with other systems — but (again) written it off as observational error. For all the world it's like I'm hearing the CPU working (as opposed to the GPU; note the window scroll thing above) or data being transferred somewhere, but that just seems...unlikely. So what am I hearing? This may seem like a very localized question, but perhaps other silent PC enthusiasts may be interested as well...

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• IBM Server Config questions

  - by Joel Coel

  I have a few questions on a potential server setup. First, the situation: Last year we bought an IBM x3500 server with 2 Xeon E5410's, 9GB RAM, 6 HDDs. The original intent for this server was to replace the old exchange e-mail server. It was brought in, set up, and then shortly after we switched to gmail. Shortly after that my predecessor left for greener pastures, and finally I was hired. So this nice server is now sitting (mostly) idle. This year I have budget again for one server, and of course I want to put this other server to work. I'm thinking about the best use for the two server, and I think I finally have a plan for what I want to do with them. The idea is to use the two newer servers as a pair of VM hosts. I will set up each server with the same 8 VMs, but divide up the load so that only 4 are active per physical host. That means I've normally got 2GB RAM + 2 cores per host. I've done some load testing to pick out what servers to convert to virtual, and chose them so that each host will be capable of handling the entire set of 8 by itself in a pinch with 1 core and 1GB RAM, but would be very taxed to do so. This should take our data center from 13 total servers down to 7. The "servers" I'm replacing are mostly re-purposed desktops, so I'm more than happy to be able to do this. Now it's time to go shopping for the new server. I'd like my two hosts to match as closely as possible, and so I'm looking at IBM again. It also helps that we have some educational matching grant money from IBM that I need to use to help pay for this system (we're a small private college). So finally, (if you're not bored already), we come to my questions: Am I missing anything big or obvious in this plan? I'm a little worried about network performance since the VM hosts will only have 4 nics total where 8 used to be, but I don't think it will be a problem. Is there anything else like this I might be overlooking? Am I making it even too complicated? IBM no longer has a good analog to last year's server. If I want to match the performance (8 cores, 9GB RAM, 1333mhz front side bus, 6 spindles), I have to spend quite a bit more than we paid last year: $2K+, or nearly a 33% cost increase. This only brings a marginal increase in performance. The alternative to stay in budget is to take a hit on the fsb down to 800mhz or cut the number of cores in half, neither of which is attractive. The main cost culprit is the processor. IBM no longer offers the E5410. It's listed as a part, but not available in any of the server configs I've looked at. I'm considering getting the cheapest 800mhz fsb dual core xeon I can configure and then buying the E5410's separately. That's still an extra $350 I wasn't counting on, but that's better than $2K. I want to know what others think of this - will it work or will I end up with the wrong motherboard or some other issue? Am I missing a simple way to configure the server I really want? I don't really intend to do this, but one option to save some money back is to omit the redundant power supply. Since my redundancy plan for these system is to switch over to a completely different host, the extra power isn't fully necessary. That said, it's still very helpful to avoid even short downtimes while I switch over VMs. Has anyone done this?

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• Windows 7 / Ubuntu Dualboot GRUB Problem.

  - by Tek

  I'd like to first say ahead of time that I'm running a RAID-0 Setup. 1.First of all, I'm glad Ubuntu 9.10 installed flawlessly and detected my RAID-0 setup just fine. The issue I'm having now is that I already had Windows 7 installed and made a small 12GB partition for Linux/Swap. I grabbed EasyBCD 2.0 to edit the W7 bootloader and configured it to use dual boot Grub2 because before it didn't even show the option for Ubuntu. The bootloader points to a file made in the windows directory made by EasyBCD called "C:\NST\AutoNeoGrub0.mbr" which is what I'm guessing grub is booting from. After that I got the option for booting Ubuntu. The problem is that it's sending me to the Grub prompt (probably because it's pointing to \NST|AutoNeoGrub0.mbr?), at first I didn't know what to do but I researched and have to type grub commands to manually boot into Ubuntu Linux. Ex: grubroot (hd0,4) grubkernel /boot/vmlinuz-2.6... root=/dev/disk/by-uuid/24624-2424... grubinitrd boot/initrd.img-2.6... grubboot After all that Ubuntu boots just fine, but how do I fix it permanently? Do I need to edit the bootloader manually (since Easy BCD "autoconfigures")? Some insight on this would rock! Also, it sucks to type the actual uuid since it's REALLY long. I tried getting the name of the drive via fdisk -l but since it's raid 0 I'm guessing I can't do that. How can I get a shorter name of the drive? like /dev/sda, /dev/sdb etc? I've also tried to update to the latest GRUB and I got this: Creating config file /etc/default/grub with new version Generating core.img error: cannot seek /dev/sdc' error: cannot seek/dev/sdc' grub-probe: error: no mapping exists for nvidia_dbedfcca5' Auto-detection of a filesystem module failed. Please specify the module with the option--modules' explicitly. dpkg: error processing grub-pc (--configure): subprocess installed post-installation script returned error exit status 1 dpkg: dependency problems prevent configuration of grub2: grub2 depends on grub-pc; however: Package grub-pc is not configured yet. dpkg: error processing grub2 (--configure): dependency problems - leaving unconfigured No apport report written because the error message indicates its a followup error from a previous failure. E: Sub-process /usr/bin/dpkg returned an error code (1) I've also tried: b@dnb:~$ sudo update-grub error: cannot seek /dev/sdc' error: cannot seek/dev/sdc' Generating grub.cfg ... Found linux image: /boot/vmlinuz-2.6.31-14-generic Found initrd image: /boot/initrd.img-2.6.31-14-generic error: cannot seek /dev/sdc' grub-probe: error: no mapping exists fornvidia_dbedfcca5' error: cannot seek /dev/sdc' grub-probe: error: no mapping exists fornvidia_dbedfcca5' Found memtest86+ image: /boot/memtest86+.bin Found Windows 7 (loader) on /dev/mapper/nvidia_dbedfcca1 error: cannot seek /dev/sdc' grub-probe: error: no mapping exists fornvidia_dbedfcca1' done To no avail. Any idea what I can do to fix this mess? :( Edit: This is my disk configuration. b@dnb:~$ sudo df -l Filesystem 1K-blocks Used Available Use% Mounted on /dev/mapper/nvidia_dbedfcca5 12302232 2744788 8932520 24% / udev 1030288 268 1030020 1% /dev none 1030288 964 1029324 1% /dev/shm none 1030288 92 1030196 1% /var/run none 1030288 0 1030288 0% /var/lock none 1030288 0 1030288 0% /lib/init/rw /dev/sr0 706532 706532 0 100% /media/cdrom0 Note: /dev/mapper/nvidia_dbedfcca5 is my Linux boot partition

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• Why would VMWare to go defunct? How to recover from/prevent it?

  - by Josh

  I am running VMWare Server 2.0.2 (Build 203138) on a dual core Intel i5 with Ubuntu Server 10.04 LTS system (kernel 2.6.32-22-server #33-Ubuntu SMP). Disk Subsystem is a software RAID5 array. The system has been set up for a little over a week. For the past 5 days I have been running at leat 3 VMs (Linux and a variety of Windows OSes) with no issues whatsoever. But while I was installing Linux onto a new VM, suddenly all VMs became unresponsive, including the one I was installing to. I could not log in to the VMWare Management Interface, and the system was somewhat unresponsive via SSH. When I looked at top, I saw: top - 16:14:51 up 6 days, 1:49, 8 users, load average: 24.29, 24.33 17.54 Tasks: 203 total, 7 running, 195 sleeping, 0 stopped, 1 zombie Cpu(s): 0.2%us, 25.6%sy, 0.0%ni, 74.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 8056656k total, 5927580k used, 2129076k free, 20320k buffers Swap: 7811064k total, 240216k used, 7570848k free, 5045884k cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 21549 root 39 19 0 0 0 Z 100 0.0 15:02.44 [vmware-vmx] <defunct> 2115 root 20 0 0 0 0 S 1 0.0 170:32.08 [vmware-rtc] 2231 root 21 1 1494m 126m 100m S 1 1.6 892:58.05 /usr/lib/vmware/bin/vmware-vmx -# product=2; 2280 jnet 20 0 19320 1164 800 R 0 0.0 30:04.55 top 12236 root 20 0 833m 41m 34m S 0 0.5 88:34.24 /usr/lib/vmware/bin/vmware-vmx -# product=2; 1 root 20 0 23704 1476 920 S 0 0.0 0:00.80 /sbin/init 2 root 20 0 0 0 0 S 0 0.0 0:00.01 [kthreadd] 3 root RT 0 0 0 0 S 0 0.0 0:00.00 [migration/0] 4 root 20 0 0 0 0 S 0 0.0 0:00.84 [ksoftirqd/0] 5 root RT 0 0 0 0 S 0 0.0 0:00.00 [watchdog/0] 6 root RT 0 0 0 0 S 0 0.0 0:00.00 [migration/1] The VMWare process for the virtual machine I was installing into became a zombie. Yet, it was still consuming 100% of the CPU time on one of the cores, and I couldn't reach it or any other virtual machines. (I was logged in to one virtual machine over SSH, another via X11, and a third via VNC. All three connections died). When I ran ps -ef and similar commands, I found that the defunct vmware-vmx process had it's parent PID set to init (1). I also used lsof -p 21549 and found that the defunct process had no open files. Yet it was using 100% of CPU time... I was unable to kill any vmware-vmx processes, including the defunct one, even with kill -9. As a last resort to resolve the situation I tried to reboot the box, however shutdown, halt, reboot, and init 6 all failed to reboot/shutdown, even when given appropriate --force settings. ControlAltDel produced a message about rebooting on the console, but the system would not reboot. I had to hard power-cycle the box to resolve the situation. (See my other question, Should I worry about the integrity of my linux software RAID5 after a crash or kernel panic?) What would cause a scenario like this? What else could I have done to resolve it besides a hard reboot? What can I do to prevent such a situation in the future?

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• My computer freezes irregurarly

  - by Manhim

  My computer started to freeze at irregular times for 3 weeks now. What happens My computer freezes, the video stops. (No graphic glitches, it just stops) Sound keeps playing up to some time (Usually 10-30 seconds) then stops playing. Sometimes, randomly, the screen on my G-15 keyboard flickers and I see caracters not at the right places. Usually happens for about 1-2 seconds and a bit before my computer freezes. I have to keep the power button pressed for 4 seconds to shut my computer down. I still hear my hard drives and fans working. Sometimes it works with no problems for a full day, some other times it just keeps freezing each time I restart my computer and I have to leave it for the rest of the day. Sometimes my mouse freezes for a fraction of a second (Like 0.01 to 0.2 seconds) quite randomly, usually before it freezes. No errors spotted by the "Action center" unlike when I had problems with my last video card on this system (Driver errors). My G-15 LCD screen also freezes. What I did so far I have had similar problems in the past and I had changed my hard drive (It was faulty), so I tested my software RAID-0 array and it was faulty so I changed it. (I reinstalled Windows 7 with this part). I also tested with unplugging my secondary hard drive. My CPU was running at about 100 degree Celsius, I removed the dust between the fans and the heatsink and it's now between 50-60. I ran a CPU stress-test and it didn't freeze during the tests (using Prime95 on all cores) Ran a memory test (using memtest86+) for a single pass and there were no errors. Ran a GPU stress test with ati-tools and furmark and it didn't freeze during the tests. (No artefacts either) I had troubles with my graphic card when I got it, but I think that it got fixed with a driver update. I checked the voltages in my BIOS setup and they all seemed ok (±0.2 I think). I have ran on the computer without problems with Fedora 15 on an external hard drive (Appart that it couldn't load Gnome 3 and was reverting to Gnome 2, didn't want to install drivers since I use it on multiple computers) I used it to backup my files from the raid array to my 1TB hard drive for the reinstallation of Windows. (So the crashes only happenned on Windows) [The external hard drive is plugged directly on a SATA port] I contacted EVGA (My graphic card vendor) and pointed them on this question, I'm looking for an answer. Ran sensors on Fedora 15 and got this output: http://pastebin.com/0BHJnAvu When it happens When I play video games (Mostly) When I play flash games (Second most) When I'm looking at my desktop background (It rarely happens when I have a window open, but it does, sometimes) Specs Windows Seven x64 Home Premium Motherboard: M2N-SLI Deluxe CPU: AMD Phenom 9950 x2 @ 2.6GHz Memory: Kingston 4x2GB Dual Channel (Pretty basic memory sticks) Hard drives: Was 2x250GB (Western digital caviar) in raid-0 + 1TB (WD caviar black), I replaced the raid array with a 750GB (WD caviar black) [Yes I removed the array from the raid configurations] 750W Power supply No overcloking. Ever. There have been some power-downs like 4-5 weeks ago, but the problem didn't start immediately after. (I wasn't home, so my computer got shut-down) My current to-try list Change the thermal paste on my CPU. Change my graphic card with a temporary one and stress the computer. Change my power supply. In this situation, how can I successfully pin-point the current hardware problem? (If it's a hardware problem) Because I don't really have the budget to just forget and replace everything. I also don't really have hardware to test-replace current hardware.

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• How to diagnose computer lockups and freezes?

  - by Scott Mitchell

  I built a desktop computer a couple years back with the following specs: CPU: Intel Core 2 Quad Q9300 Yorkfield 2.5GHz 6 MB L2 Cache LGA 775 95W Quad-Core Processor BX80580Q9300 Motherboard: EVGA 122-CK-NF68-T1 LGA 775 NVIDIA nForce 680i SLI ATX Intel Motherboard Video Card: Two EVGA 256-P2-N758-TR GeForce 8600GT SCC 256 MB 128-bit GDDR3 PCI Express x16 SLI Supported Video Card PSU: SeaSonic S12 Energy Plus SS-550HT 550W ATX12V V2.3 / EPS12V V2.91 SLI Certified CrossFire Ready 80 PLUS Certified Active PFC Power Supply Memory: Two G.SKILL 4 GB (2 x 2 GB) 240-Pin DDR2 SDRAM DDR2 800 (PC2 6400) Dual Channel Kit Desktop Memory Model F2-6400CL5D-4GBPQ Since its inception, the machine has periodically locked up, the regularity having varied over the years from once a day to once a month. Typically, lockups happen once every few days. By "lockup" I mean my computer just freezes. The screen locks up, I can't move the mouse. Hitting keys on my keyboard that normally turn LEDs on or off on the keyboard (such as Caps Lock) no longer turn the LEDs on or off. If there was music playing at the time of the lockup, noise keeps coming out of the speakers, but it's just the current frequency/note that plays indefinitely. There is no BSOD. When such a lockup occurs I have to do a hard reboot by either turning off the computer or hitting the reset button. I have the most recent version of the NVIDIA hardware drivers, and update them semi-regularly, but that hasn't seemed to help. I am currently using Windows 7 x64, but was previously using Windows Server 2003 x64 and having the same lockup issues. My guess is that it's somehow video driver or motherboard related, but I don't know how to go about diagnosing this problem to narrow down which of the two is the culprit. Additional information re: cooling Regarding cooling... I've not installed any after-market cooling systems aside from two regular fans I scavenged from an older computer. The fan atop the CPU is the one that shipped with it. One of the two scavenged fans I added it located at the bottom tower of the corner, in an attempt to create some airflow from front to back. The second fan is pointed directly at the two video cards. SpeedFan installation and readings Per studiohack's suggestion, I installed SpeedFan, which provided the following temperature readings: GPU: 63C GPU: 65C System: 76C CPU: 64C AUX: 36C Core 0: 78C Core 1: 76C Core 2: 79C Core 3: 79C Update #3: Another Lockup :-( Well, I had another lockup last night. :-( SpeedFan reported the CPU temp at 38 C when it happened, and there was no spike in temperature leading up to the freeze. One thing I notice is that the freeze seems more likely to happen if I am watching a video. In fact, of the last 5 freezes over the past month, 4 of them have been while watching a video on Flickr. Not necessarily the same video, but a video nevertheless. I don't know if this is just coincidence or if it means anything. (As an aside, each night before bedtime my 2 year old daughter sits on my lap and watches some home videos on Flickr and, in the last month, has learned the phrase, "Uh oh, computer broke.") Update #4: MemTest86 and 3DMark06 Test Results: Per suggestions in the comments, I ran the MemTest86 overnight and it cycled through the 8 GB of memory 5 times without error. I also ran the 3DMark06 test without a problem (see my scores at http://3dmark.com/3dm06/15163549). So... what now? :-) Any further suggestions on what to check? Is there some way to get a stack trace or something when the computer locks like that? Resolution I have never did figure out the particular problems, but based on the suggestions here and elsewhere, I'm presuming it was a motherboard issue. In any event, I recently upgraded my system, buying a new motherbeard, PSU, CPU, and RAM, and that new rig has been working splendidly the past several weeks. I am using the same graphic cards as in the old setup, so I think it's safe to reason that they weren't the cause of the problem.

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• VMware vSphere cluster design for site redundancy

  - by Stefan Radovanovici

  I have a question about the best design for site redudancy when using vSphere clusters. A bit of background info about our situation first though. We are a medium-sized company with two main offices, located in different countries. Our networks are linked by a Layer2 150Mbps leased line which is currently underused. We have a variety of services running for internal use within the company, some on physycal servers and some on existing vSphere clusters. In our department we also run several services (almost all running under various forms of Linux) like NTP, Syslog, jump servers, monitoring servers and so on. We have now the requirement that those servers need to be redundant within each location (which they are not at the moment) and also site redudant (which they are to some extent, the servers are duplicated in the 2nd location with configurations kept in sync via various methods at the application layer). There is no SAN available for us, at least not something that we can use at the moment. Cost is also an issue. While we do have some budget available for this, we can't afford to buy SANs for both locations for example. I looked at the VSA feature and it seems that this could be something for us but I am unsure how to solve the site-redudancy requirement. At the moment for testing purposes I am setting up in a lab a vSphere 5 with VSA on two ESXi hosts. I am currently using the Essentials Plus kit with VSA license, which allows me to build a VSA cluster on up to 3 hosts, together with a vCenter license to manage them. The hosts each have two dual-port network cards and two 600GB drives, running in Raid1. Hardware-wise this will be enough for us to run the all the services we need as VMs and will provide redundandcy within the site. At the moment I see only two option to have site redundancy: build an identical VSA cluter in the second location and keep the various services sync'ed at application layer (database sync, rsync and so on). simply move one of the hosts from the existing cluster to the second location, basically having the VSA cluster span the 150Mbps link between the sites. I would very much prefer the second option but I am unsure how well it'll work, if it can work at all. Technically it should, we can span the needed VLANs across the leased line and have them available in the second location. The advantage would be that we don't need to worry at all about sync'ing databases and the like. But I have the feeling that the bandwidth will not be enough, I have no way of knowing how much traffic will the VSA cluster generate between the hosts. I realize that this will most likely depend on the individual usage of the VMs but still, I have no idea how VSA replicates data between the ESXi hosts. Are these my only options or can my goals be achieved in some other way ? Is there perhaps a way to have some sort of "cold stand by" cluster in the second location where the VMs would be sync'ed once per night from the main location ? The idea is that in case the first site becomes unavailable, we would be able to bring all those VMs online there. We would be ok with the data being 1 day old. Any answers are appreciated. Best regards, Stefan

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• Week in Geek: LastPass Rescues Xmarks Edition

  - by Asian Angel

  This week we learned how to breathe new life into an aging Windows Mobile 6.x device, use filters in Photoshop, backup and move VirtualBox machines, use the BitDefender Rescue CD to clean an infected PC, and had fun setting up a pirates theme on our computers. Photo by _nash. Weekly Feature Do you love using the Faenza icon set on your Ubuntu system but feel that there are a few much needed icons missing (or you desire a different version of a particular icon)? Then you may want to take a look at the Faenza Variants icon pack. The icons are available in the following sizes: 16px, 22px, 32px, 48px and scalable sizes. Photo by Asian Angel. Faenza Variants Random Geek Links Another week with extra link goodness to help keep you on top of the news. Photo by Asian Angel. LastPass acquires Xmarks, premium service announced Xmarks announced that it has been acquired by LastPass, a cross-platform password management service. This also means that Xmarks is now in transition from a “free” to a “freemium” business model. WikiLeaks reappears on European Net domains WikiLeaks has re-emerged on a Swiss Internet domain followed by domains in Germany, Finland, and the Netherlands, sidestepping a move that had in effect taken the controversial site off the Internet. Iran: Yes, Stuxnet hurt our nuclear program The Stuxnet worm got some big play from Iranian President Mahmoud Ahmadinejad, who acknowledged that the malware dinged his nuclear program. More Windows Rogues than Just AV – Fake Defragmenter Check Disk Don’t think for a second that rogues are limited to scareware, because as so-called products such as “System Defragmenter”, “Scan Disk” “Check Disk” prove, they’re not. Internet Explorer’s Protected Mode can be bypassed Researchers from Verizon Business have now described a way of bypassing Protected Mode in IE 7 and 8 in order to gain access to user accounts. Can you really see who viewed your Facebook profile? Rogue application spreads virally Once again, a rogue application is spreading virally between Facebook users pretending to offer you a way of seeing who has viewed your profile. More holes in Palm’s WebOS Researchers Orlando Barrera and Daniel Herrera, who both work for security firm SecTheory, have discovered a gaping security hole in Palm’s WebOS smartphone operating system. Next-gen banking Trojans hit APAC With the proliferation of banking Trojans, Web and smartphone users of online banking services have to be on constant alert to avoid falling prey to fraud schemes, warned Etay Maor, project manager for RSA Fraud Action. AVG update cripples 64-bit computers A signature update automatically deployed by the AVG virus scanner Thursday has crippled numerous computers. Article includes link to forums to fix computers affected after a restart. Congress moves to outlaw ‘mystery charges’ for Web shoppers Legislation that makes it illegal for Web merchants and so-called post-transaction marketers to charge credit cards without the card owners’ say-so came closer to becoming law this week. Ballmer Set to “Look Into” Windows Home Server Drive Extender Fiasco Tuesday’s announcement from Microsoft regarding the removal of Drive Extender from Windows Home Server has sent shock waves across the web. Google tweaks search recipe to ding scam artists Google has changed its search algorithm to penalize sites deemed to provide an “extremely poor user experience” following a New York Times story on a merchant who justified abusive behavior towards customers as a search-engine optimization tactic. Geek Video of the Week Watch as our two friends debate back and forth about the early adoption of new technology through multiple time periods (Stone Age to the far future). Will our reluctant friend finally succumb to the temptation? Photo by CollegeHumor. Early Adopters Through History Random TinyHacker Links Fix Issues in Windows 7 Using Reliability Monitor Learn how to analyze Windows 7 errors and then fix them using the built-in reliability monitor. Learn About IE Tab Groups Tab groups is a useful feature in IE 8. Here’s a detailed guide to what it is all about. Google’s Book Helps You Learn About Browsers and Web A cool new online book by the Google Chrome team on browsers and the web. TrustPort Internet Security 2011 – Good Security from a Less Known Provider TrustPort is not exactly a well-known provider of security solutions. At least not in the consumer space. This review tests in detail their latest offering. How the World is Using Cell phones An infographic showing the shocking demographics of cell phone use. Super User Questions See the great answers to these questions from Super User. I am unable to access my C drive. It says it is unable to display current owner. List of Windows special directories/shortcuts like ‘%TEMP%’ Is using multiple passes for wiping a disk really necessary? How can I view two files side by side in Notepad++ Is there any tool that automatically puts screenshots to my Dropbox? How-To Geek Weekly Article Recap Look through our hottest articles from this past week at How-To Geek. How to Create a Software RAID Array in Windows 7 9 Alternatives for Windows Home Server’s Drive Extender Why Doesn’t Disk Cleanup Delete Everything from the Temp Folder? Ask the Readers: How Much Do You Customize Your Operating System? How to Upload Really Large Files to SkyDrive, Dropbox, or Email One Year Ago on How-To Geek Enjoy reading through these awesome articles from one year ago. How To Upgrade from Vista to Windows 7 Home Premium Edition How To Fix No Aero Transparency in Windows 7 Troubleshoot Startup Problems with Startup Repair Tool in Windows 7 & Vista Rename the Guest Account in Windows 7 for Enhanced Security Disable Error Reporting in XP, Vista, and Windows 7 The Geek Note That wraps things up here for this week. Regardless of the weather wherever you may be, we hope that you have an opportunity to get outside and have some fun! Remember to keep sending those great tips in to us at [email protected]. Photo by Tony the Misfit. Latest Features How-To Geek ETC The How-To Geek Guide to Learning Photoshop, Part 8: Filters Get the Complete Android Guide eBook for Only 99 Cents [Update: Expired] Improve Digital Photography by Calibrating Your Monitor The How-To Geek Guide to Learning Photoshop, Part 7: Design and Typography How to Choose What to Back Up on Your Linux Home Server How To Harmonize Your Dual-Boot Setup for Windows and Ubuntu Hang in There Scrat! – Ice Age Wallpaper How Do You Know When You’ve Passed Geek and Headed to Nerd? On The Tip – A Lamborghini Theme for Chrome and Iron What if Wile E. Coyote and the Road Runner were Human? [Video] Peaceful Winter Cabin Wallpaper Store Tabs for Later Viewing in Opera with Tab Vault

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• Eine komplette Virtualisierungslandschaft auf dem eigenen Laptop – So geht’s

  - by Manuel Hossfeld

  Eine komplette Virtualisierungslandschaftauf dem eigenen Laptop – So geht’s Wenn man sich mit dem Virtualisierungsprodukt Oracle VM in der aktuellen Version 3.x näher befassen möchte, bietet es sich natürlich an, eine eigene Umgebung zu Lern- und Testzwecken zu installieren. Doch leichter gesagt als getan: Bei näherer Betrachtung der Architektur wird man schnell feststellen, dass mehrere Rechner benötigt werden, um überhaupt alle Komponenten abbilden zu können: Zum einen gilt es, den oder die OVM Server selbst zu installieren. Das ist recht leicht und schnell erledigt, aber da Oracle VM ein „Typ 1 Hypervisor ist“ - also direkt auf dem Rechner („bare metal“) installiert wird – ist der eigenen Arbeits-PC oder Laptop dafür recht ungeeignet. (Eine Dual-Boot Umgebung wäre zwar denkbar, aber recht unpraktisch.) Zum anderen wird auch ein Rechner benötigt, auf dem der OVM Manager installiert wird. Im Gegensatz zum OVM Server erfolgt dessen Installation nicht „bare metal“, sondern auf einem bestehenden Oracle Linux. Aber was tun, wenn man gerade keinen Linux-Server griffbereit hat und auch keine extra Hardware dafür opfern will? Möchte man alle Funktionen von Oracle VM austesten, so sollte man zusätzlich über einen Shared Storag everüfugen. Dieser kann wahlweise über NFS oder über ein SAN (per iSCSI oder FibreChannel) angebunden werden. Zwar braucht man zum Testen nicht zwingend entsprechende „echte“ Storage-Hardware, aber auch die „Simulation“ entsprechender Komponenten erfordert zusätzliche Hardware mit entsprechendem freien Plattenplatz.(Alternativ können auch fertige „Software Storage Appliances“ wie z.B. OpenFiler oder FreeNAS verwendet werden). Angenommen, es stehen tatsächlich keine „echte“ Server- und Storage Hardware zur Verfügung, so benötigt man für die oben genannten drei Punkte  drei bzw. vier Rechner (PCs, Laptops...) - je nachdem ob man einen oder zwei OVM Server starten möchte. Erfreulicherweise geht es aber auch mit deutlich weniger Aufwand: Wie bereits kurz im Blogpost anlässlich des letzten OVM-Releases 3.1.1 beschrieben, ist die aktuelle Version in der Lage, selbst vollständig innerhalb von VirtualBox als Gast zu laufen. Wer bei dieser „doppelten Virtualisierung“ nun an das Prinzip der russischen Matroschka-Puppen denkt, liegt genau richtig. Oracle VM VirtualBox stellt dabei gewissermaßen die äußere Hülle dar – und da es sich bei VirtualBox im Gegensatz zu Oracle VM Server um einen „Typ 2 Hypervisor“ handelt, funktioniert dieser Ansatz auch auf einem „normalen“ Arbeits-PC bzw. Laptop, ohne dessen eigentliche Betriebsystem komplett zu überschreiben. Doch das beste dabei ist: Die Installation der jeweiligen VirtualBox VMs muss man nicht selber durchführen. Der OVM Manager als auch der OVM Server stehen bereits als vorgefertigte „VirtualBox Appliances“ im Oracle Technology Network zum Download zur Verfügung und müssen im Grunde nur noch importiert und konfiguriert werden. Das folgende Schaubild verdeutlicht das Prinzip: Die dunkelgrünen Bereiche stellen jeweils Instanzen der eben erwähnten VirtualBox Appliances für OVM Server und OVM Manager dar. (Hier im Bild sind zwei OVM Server zu sehen, als Minimum würde natürlich auch einer genügen. Dann können aber viele Features wie z.B. OVM HA nicht ausprobieren werden.) Als cleveren Trick zur Einsparung einer weiteren VM für Storage-Zwecke hat Wim Coekaerts (Senior Vice President of Linux and Virtualization Engineering bei Oracle), der „Erbauer“ der VirtualBox Appliances, die OVM Manager Appliance bereits so vorbereitet, dass diese gleichzeitig als NFS-Share (oder ggf. sogar als iSCSI Target) dienen kann. Dies beschreibt er auch kurz auf seinem Blog. Die hellgrünen Ovale stellen die VMs dar, welche dann innerhalb einer der virtualisierten OVM Server laufen können. Aufgrund der Tatsache, dass durch diese „doppelte Virtualisierung“ die Fähigkeit zur Hardware-Virtualisierung verloren geht, können diese „Nutz-VMs“ demzufolge nur paravirtualisiert sein (PVM). Die hier in blau eingezeichneten Netzwerk-Schnittstellen sind virtuelle Interfaces, welche beliebig innerhalb von VirtualBox eingerichtet werden können. Wer die verschiedenen Netzwerk-Rollen innerhalb von Oracle VM im Detail ausprobieren will, kann hier natürlich auch mehr als zwei dieser Interfaces konfigurieren. Die Vorteile dieser Lösung für Test- und Demozwecke liegen auf der Hand: Mit lediglich einem PC bzw. Laptop auf dem VirtualBox installiert ist, können alle oben genannten Komponenten installiert und genutzt werden – genügend RAM vorausgesetzt. Als Minimum darf hier 8GB gelten. Soll auf der „Host-Umgebung“ (also dem PC auf dem VirtualBox läuft) nebenbei noch gearbeiten werden und/oder mehrere „Nutz-VMs“ in dieser simulierten OVM-Server-Umgebung laufen, empfehlen sich natürlich eher 16GB oder mehr. Da die nötigen Schritte zum Installieren und initialen Konfigurieren der Umgebung ausführlich in einem entsprechenden Paper beschrieben sind, möchte ich im Rest dieses Artikels noch einige zusätzliche Tipps und Details erwähnen, welche einem das Leben etwas leichter machen können: Um möglichst entstpannt und mit zusätzlichen „Sicherheitsnetz“ an die Konfiguration der Umgebung herangehen zu können, empfiehlt es sich, ausgiebigen Gebrauch von der in VirtualBox eingebauten Funktionalität der VM Snapshots zu machen. Dies ermöglicht nicht nur ein Zurücksetzen falls einmal etwas schiefgehen sollte, sondern auch ein beliebiges Wiederholen von bereits absolvierten Teilschritten (z.B. um eine andere Idee oder Variante der Umgebung auszuprobieren). Sowohl bei den gerade erwähnten Snapshots als auch bei den VMs selbst sollte man aussagekräftige Namen verwenden. So ist sichergestellt, dass man nicht durcheinander kommt und auch nach ein paar Wochen noch weiß, welche Umgebung man da eigentlich vor sich hat. Dies beinhaltet auch die genaue Versions- und Buildnr. des jeweiligen OVM-Releases. (Siehe dazu auch folgenden Screenshot.) Weitere Informationen und Details zum aktuellen Zustand sowie Zweck der jeweiligen VMs kann in dem oft übersehenen Beschreibungsfeld hinterlegt werden. Es empfiehlt sich, bereits VOR der Installation einen Notizzettel (oder eine Textdatei) mit den geplanten IP-Adressen und Namen für die VMs zu erstellen. (Nicht vergessen: Auch der Server Pool benötigt eine eigene IP.) Dabei sollte man auch nochmal die tatsächlichen Netzwerke der zu verwendenden Virtualbox-Interfaces prüfen und notieren. Achtung: Es gibt im Rahmen der Installation einige Passworte, die vom Nutzer gesetzt werden können – und solche, die zunächst fest eingestellt sind. Zu letzterem gehört das Passwort für den ovs-agent sowie den root-User auf den OVM Servern, welche beide per Default „ovsroot“ lauten. (Alle weiteren Passwort-Informationen sind in dem „Read me first“ Dokument zu finden, welches auf dem Desktop der OVM Manager VM liegt.) Aufpassen muss man ggf. auch in der initialen „Interview-Phase“ welche die VirtualBox VMs durchlaufen, nachdem sie das erste mal gebootet werden. Zu diesem Zeitpunkt ist nämlich auf jeden Fall noch die amerikanische Tastaturbelegung aktiv, so dass man z.B. besser kein „y“ und „z“ in seinem selbst gewählten Passwort verwendet. Aufgrund der Tatsache, dass wie oben erwähnt der OVM Manager auch gleichzeitig den Shared Storage bereitstellt, sollte darauf geachtet werden, dass dessen VM vor den OVM Server VMs gestartet wird. (Andernfalls „findet“ der dem OVM Server Pool zugrundeliegende Cluster sein sog. „Server Pool File System“ nicht.)

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