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  • Where can I find the supported way to deploy hadoop on precise?

    - by Jeff McCarrell
    I want to set up a small (6 node) hadoop/hive/pig cluster. I see the work in the juju space on charms; however, the current status of deploying a single charm per node will not work for me. I see ServerTeam Hadoop which talks about re-packaging the bigtop packages. The cloudera CDH3 installation guide talks about Maverick and Lucid, but not precise. What am I missing? Is there a straight forward way to deploy hadoop/hive/pig on 6 nodes that does not involve building from tarballs?

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  • Android, OpenGL and extending GLSurfaceView?

    - by Spoon Thumb
    This question is part-technical, part-meta, part-subjective and very specific: I'm an indie game dev working on android, and for the past 6 months I've struggled and finally succeeded in making my own 3D game app for android. So I thought I'd hop on SO and help out others struggling with android and openGL-ES However, the vast majority of questions relate to extending GLSurfaceView. I made my whole app without extending GLSurfaceView (and it runs fine). I can't see any reason at all to extend GLSurfaceView for the majority of questions I come across. Worse, the android documentation implies that you ought to, but gives no detailed explaination of why or what the pros/cons are vs not extending and doing everything through implementing your own GLSurfaceView.Renderer as I did Still, the sheer volume of questions where the problem is purely to do with extending GLSurfaceView is making me wonder whether actually there is some really good reason for doing it that way vs the way I've been doing it (and suggesting in my answers to others to do). So, is there something I'm missing? Should I stop answering questions in the meantime? Android openGL documentation

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  • How to safely copy an object?

    - by Prog
    This question is going to be a little long. Please bear with me. Something that happened in a project of mine made me think about how to safely copy objects. I'll present the situation I had and then ask a question. There was a class SomeClass: class SomeClass{ Thing[] things; public SomeClass(Thing[] things){ this.things = things; } // irrelevant stuff omitted public SomeClass copy(){ return new SomeClass(things); } } There was another class Processor that takes SomeClass objects, copies them (via someClassInstance.copy()), manipulates the copy's state, and returns the copy. Here it is: class Processor{ public SomeClass processObject(SomeClass object){ SomeClass copy = object.copy(); manipulateTheCopy(copy); return copy; } // irrelevant stuff omitted } I ran this, and it had bugs. I looked into these bugs, and it turned out that the manipulations Processor does on copy actually affect not only the copy, but also the original SomeClass object that was passed into processObject. I found out that it was because the original and the copy shared state - because the original passed it's field things into the copy when creating it. This made me realize that copying objects is harder than simply instantiating them with the same fields as the original. For the two objects to be completely disconnected, without any shared state, each of the fields passed to the copy also has to be copied. And if that object contains other objects - they have to be copied too. And so on. So basically, in order to be able to actually copy an object, each class in the system must have a copy() method, that also invokes copy() on all of it's fields, and so on. So for example, for copy() in SomeClass to work, it needs to look like this: public SomeClass copy(){ Thing[] copyThings = new Thing[things.length]; for(int i=0; i<things.length; i++) copyThings[i] = things[i].copy(); return new SomeClass(copyThings); } And if Thing has object fields of it's own, than it's own copy() method must be appropriate: class Thing{ Apple apple; Pencil pencil; int number; public Thing(Apple apple, Pencil pencil, int number){ this.apple = apple; this.pencil = pencil; this.number = number; } public Thing copy(){ // 'number' is a primitve. return new Thing(apple.getCopy(), pencil.getCopy(), number); } } And so on. Of course, instead of all classes having a copy() method, the copying mechanism can happen in all of the getters and the constructors of classes (unless places where it isn't suitable, for example when the field points to an external object, not to an object that 'is part' of this object). Still, that means that in order to be able to safely copy an object - most classes would have to have copying mechanisms in their getters. My question is divided into two parts: How frequently do you need to get a copy of an object? Is this a regular issue? Is the technique described common and/or reasonable? Or is there a better way to make safe copies of objects? Or is there an easier way to safely copy objects, without them sharing any state?

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  • Uninstalling Ubuntu dual-boot bootrec issues

    - by Raymond Standen
    So on my laptop I am currently planning on uninstalling Ubuntu 12.04 so I can upgrade my Windows 7 partition to Windows 8, then install Ubuntu 12.10. My issue being that when I boot the Windows 7 recovery disk, I believe i Need to use cmd to run bootrec /fixboot and bootrec /fixmbr. Now, whilst fixmbr works, fixboot yields me with an error regarding an unrecognised volume. When I turn on my PC now, I am no longer met the GRUB option, so I boot straight into Windows. My question is: As such, do I still need to have fixboot run or can I just format and resize the partitions now even with the error when running fixboot?

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  • How to Remotely Shut Down or Restart Windows PCs

    - by Chris Hoffman
    Windows includes Shutdown.exe, a simple utility for remotely shutting down or restarting Windows computers on your local network. To use Shutdown.exe, you must first configure the PCs you want to shut down or restart remotely. Once you’ve configured the PCs, you can use a graphical user interface or command to restart the PCs from another Windows system. You can even remotely shut down or restart the PCs from a Linux system. How To Properly Scan a Photograph (And Get An Even Better Image) The HTG Guide to Hiding Your Data in a TrueCrypt Hidden Volume Make Your Own Windows 8 Start Button with Zero Memory Usage

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  • Mounting ntfs windows drive and retrieving its data

    - by Sarmad
    Hej, A friend gave me his laptop which had problems with booting (windows). He claims his data on the drive to be retrieved and saved. I have Linux Ubuntu Server to mount its hard drive and check the contents. Now when I have mounted it I see only boot.sdi, sources, System Volume Information I have no idea why is it so? How can I access and retrieve the contents? results of sudo fdisk -l are as follows: Enhet Start Början Slut Block Id System /dev/sdb1 2048 3074047 1536000 27 Hidden NTFS WinRE /dev/sdb2 * 3074048 246945791 121935872 7 HPFS/NTFS/exFAT /dev/sdb3 246945792 416354295 84704252 7 HPFS/NTFS/exFAT /dev/sdb4 416354304 488394751 36020224 f W95 Utökad (LBA) /dev/sdb5 416356352 488394751 36019200 7 HPFS/NTFS/exFAT Please help me in this regard.

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  • Problem with .sh file

    - by omgzor
    I don't have any experience writing .sh files. I want to run the pvm2raw utility of this app from the Volume Library. I get the following error when running build.sh in Ubuntu 10.10. build.sh is as follows: # make command set mmfile=V3Makefile set make="make -f $mmfile" set rule=$1 if ($rule == "") set rule="all" // line 16 if ($rule == "deps") then if ($HOSTTYPE == "iris4d") $make MAKEDEPEND="CC -M" OPTS="-DHAVE_CONFIG_H -DVIEWER_HAVE_DCMTK" TARGET=IRIX depend if ($HOSTTYPE == "i386") $make MAKEDEPEND="c++ -M -I/usr/X11R6/include" OPTS="-DHAVE_CONFIG_H -DVIEWER_HAVE_DCMTK" TARGET=LINUX depend What's wrong there? Edit: I followed kniwor's advice and installed csh. Now I get the following error: How can I solve this Undefined variable problem?

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  • Building Cloud Infrastructure? Don't Miss this Webcast with SEI

    - by Zeynep Koch
    WEBCAST: How did Oracle Linux Enable SEI to Save in Infrastructure Costs and Improve Business Response Date: Tuesday, October 30, 2012 Time: 9:00 AM PDT Using the Oracle technology stack, SEI, a leading provider of wealth management solutions, developed an innovative, global platform for its business. That platform is built on a highly integrated infrastructure, operating system, and middleware that allows the organization to scale with customer demand. In this Webcast, join SEI’s Martin Breslin as he discusses: Why and how SEI migrated from a mainframe-based infrastructure to an x86-based infrastructure on Oracle Linux Why SEI chose Oracle Linux, Oracle Enterprise Manager, and Oracle Real Application Cluster for its platform-as-a-service (PaaS) environment How Oracle Linux enabled SEI to save costs and improve response time Key success factors and lessons learned when deploying an enterprise cloud Speakers: Martin Breslin, Senior Infrastructure Architect, SEI Global Monica Kumar, Senior Director, Oracle Linux, Virtualization and MySQL Product Marketing  Register TODAY

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  • Why do HDFS clusters have only a single NameNode?

    - by grautur
    I'm trying to understand better how Hadoop works, and I'm reading The NameNode is a Single Point of Failure for the HDFS Cluster. HDFS is not currently a High Availability system. When the NameNode goes down, the file system goes offline. There is an optional SecondaryNameNode that can be hosted on a separate machine. It only creates checkpoints of the namespace by merging the edits file into the fsimage file and does not provide any real redundancy. Hadoop 0.21+ has a BackupNameNode that is part of a plan to have an HA name service, but it needs active contributions from the people who want it (i.e. you) to make it Highly Available. from http://wiki.apache.org/hadoop/NameNode So why is the NameNode a single point of failure? What is bad or difficult about having a complete duplicate of the NameNode running as well?

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  • Extremely Hybrid Game requirements

    - by tugrul büyükisik
    What system specifications would a game need if it was: Total players per planet: ~20000 Total players per team:~1M Total players per map(small volume of space or small surface over a planet): ~2000 Total players: ~10M(world has more players than this amount i think) Two of the players are commanders of opposite quadrants(from HUD of a strategy game). Lots of players use space-crafts as a captain(like 3d fps and rts). Many many players control consoles in those space-crafts as under command of captains.(fps ) Some players are still in stone-age trying to reinvent wheel in some planet. Players design and construct any vehicles they have. With good physics engine Has puzzles inside. Everyone get experience by doing stuff(RPG). Commerce, income or totally different resource-based group(like starcraft) Player classes(primitive: cunning and strong, wrapped: healthy, wealthy) Arcade top-down style firing with ships when people get bored very low chance of miraculous things.(mediclorians, wormholes, bugs) Different game-modes: persistent(living world), resetted periodically(a new chance for noobs), instant(pre-built space + hack&slash) I suspect this would need 128GB ram and 2048 cores.

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  • Why there suddenly were so many 400 request in my access log?

    - by LotusH
    Below are little part of my access_log 118.186.8.50 - - [19/Dec/2011:22:42:57 +0800] "-" 400 0 "-" "-" 05 118.186.8.50 - - [19/Dec/2011:22:42:57 +0800] "-" 400 0 "-" "-" 06 118.186.8.50 - - [19/Dec/2011:22:42:57 +0800] "-" 400 0 "-" "-" 07 118.186.8.50 - - [19/Dec/2011:22:42:57 +0800] "-" 400 0 "-" "-" 08 118.186.8.50 - - [19/Dec/2011:22:42:57 +0800] "-" 400 0 "-" "-" 09 220.173.136.39 - - [19/Dec/2011:22:43:22 +0800] "-" 400 0 "-" "-" 10 220.173.136.39 - - [19/Dec/2011:22:43:22 +0800] "-" 400 0 "-" "-" 11 220.173.136.39 - - [19/Dec/2011:22:43:22 +0800] "-" 400 0 "-" "-" 12 220.173.136.39 - - [19/Dec/2011:22:43:22 +0800] "-" 400 0 "-" "-" 13 220.173.136.39 - - [19/Dec/2011:22:43:22 +0800] "-" 400 0 "-" "-" 14 220.173.136.39 - - [19/Dec/2011:22:43:22 +0800] "-" 400 0 "-" "-" And the volume was very huge, some like one hundred thousand of these 400 request per second. And I'm pretty sure there are no errors on my site in that period of time.(No error report and I didn't change the source code)

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  • DBA Best Practices - A Blog Series: Episode 2 - Password Lists

    - by Argenis
      Digital World, Digital Locks One of the biggest digital assets that any company has is its secrets. These include passwords, key rings, certificates, and any other digital asset used to protect another asset from tampering or unauthorized access. As a DBA, you are very likely to manage some of these assets for your company - and your employer trusts you with keeping them safe. Probably one of the most important of these assets are passwords. As you well know, the can be used anywhere: for service accounts, credentials, proxies, linked servers, DTS/SSIS packages, symmetrical keys, private keys, etc., etc. Have you given some thought to what you're doing to keep these passwords safe? Are you backing them up somewhere? Who else besides you can access them? Good-Ol’ Post-It Notes Under Your Keyboard If you have a password-protected Excel sheet for your passwords, I have bad news for you: Excel's level of encryption is good for your grandma's budget spreadsheet, not for a list of enterprise passwords. I will try to summarize the main point of this best practice in one sentence: You should keep your passwords on an encrypted, access and version-controlled, backed-up, well-known shared location that every DBA on your team is aware of, and maintain copies of this password "database" on your DBA's workstations. Now I have to break down that statement to you: - Encrypted: what’s the point of saving your passwords on a file that any Windows admin with enough privileges can read? - Access controlled: This one is pretty much self-explanatory. - Version controlled: Passwords change (and I’m really hoping you do change them) and version control would allow you to track what a previous password was if the utility you’ve chosen doesn’t handle that for you. - Backed-up: You want a safe copy of the password list to be kept offline, preferably in long term storage, with relative ease of restoring. - Well-known shared location: This is critical for teams: what good is a password list if only one person in the team knows where it is? I have seen multiple examples of this that work well. They all start with an encrypted database. Certainly you could leverage SQL Server's native encryption solutions like cell encryption for this. I have found such implementations to be impractical, for the most part. Enter The World Of Utilities There are a myriad of open source/free software solutions to help you here. One of my favorites is KeePass, which creates encrypted files that can be saved to a network share, Sharepoint, etc. KeePass has UIs for most operating systems, including Windows, MacOS, iOS, Android and Windows Phone. Other solutions I've used before worth mentioning include PasswordSafe and 1Password, with the latter one being a paid solution – but wildly popular in mobile devices. There are, of course, even more "enterprise-level" solutions available from 3rd party vendors. The truth is that most of the customers that I work with don't need that level of protection of their digital assets, and something like a KeePass database on Sharepoint suits them very well. What are you doing to safeguard your passwords? Leave a comment below, and join the discussion! Cheers, -Argenis

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  • "Wireless disabled by hardware switch" after suspend and other hardware buttons ineffective - how can I solve this?

    - by fahadayaz
    I have recently purchased a Novatech nFinity N1410 laptop and am having problems with the wireless, which sudo lshw -C network tells me is Centrino Wireless-N 2230 and using the iwlwifi driver. The problem is that after the device has been suspended, I am not able to get the wireless working again without a restart. The network indicator states that the wireless disabled by hardware switch. Though Fn+F2 is meant to be the wireless switch, xev tells me that the system doesn't see it as anything at all when I press this hardware combination. Also, though the brightness up/down buttons work fine, the volume up/down buttons do not work either. What can I do to fix this? I am running Ubuntu 12.10 with all available updates installed.

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  • Unimportant words on page being seen as keywords, due to repetiveness

    - by user21100
    I have a list of products on my site, and each product has a number of descriptors such as features, price, etc. Next to each product, I list the 10 features, with a graphical icon which lets the user know whether the product has that particular feature or not. In all, I have about 230 products, and I have to add the same list of features to describe each product, so you can see the enormous redundancy here of these "feature names". These "feature names", ex., "water proof", are not important keywords at all, yet due to the sheer volume of these words, Google is seeing them as my most important keywords. Is there any way to get around this, or to tell the bots to place (less) emphasis on these repetitive words, and not view them as important keywords?

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  • Windows 2008 R2 and Windows 7 SP1 released to manufacturers

    - by Ryan Roussel
    SP1 went RTM today which means it will be widely available soon. According  to the Microsoft server division blog, the service pack will be available to Microsoft's TechNet and MSDN subscribers, as well as to Microsoft volume licensing customers, on Feb. 16, 2011. It will be generally available via the Microsoft Download Center and Windows Update on Feb. 22   You can see the blog and news here: http://blogs.technet.com/b/windowsserver/archive/2011/02/08/windows-server-2008-r2-and-windows-7-sp1-releases-to-manufacturing-today.aspx   New features in SP1 include dynamic memory for Hyper-V VMs and RemoteFX which enables rich desktop content for Virtual Desktop Infrastructure.

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  • What has the most efficient intersection test against an AABB tree - OBB, Cylinder or Capsule?

    - by identitycrisisuk
    I'm currently trying to find collisions in 3D between a tighter volume than an AABB and a tree of AABB volumes. I just need to know whether they are intersecting, no closest distance or collision response. An OBB, Cylinder or Capsule would all roughly fit these purposes but Cylinder and Capsule were the first thing I thought of, which I have found little information about detecting intersections online. Am I right in thinking that they would always be more complex to perform Separating Axis Tests on even though they might seem like simpler shapes? I figure by the time I get my head around SAT for curved shapes I could have done the thing with OBBs but I wanted to find out for sure.

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  • I'm trying to install postgresql on 12.04, and it's just not working

    - by Pointy
    I've got a new installation and I'm trying to get Postgresql working. The database was installed and I started a restoration from a dump on another machine, but that ran into problems because I had forgotten to install the "contrib" package. I used "pg_dropcluster" to drop the old cluster so I could start from scratch, and that's when things went weird. The first manifestation of this was that /etc/postgresql was just empty. I uninstalled the postgresql package and reinstalled, several times, to no avail. Is there something I can do to figure out why apt is confused here? I've done this many times on many systems and never seen anything like this happen.

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  • Free hosting solution for a very low-traffic website [duplicate]

    - by user966939
    This question already has an answer here: How to find web hosting that meets my requirements? 4 answers I run a very low-traffic website (about 40 users, basically all of which are daily active on the site). I don't see it changing anytime soon either, as there is no way to sign up on the site right now. Until now I have just been using a sub-directory on a friend's host (shared), to host the web site. But in only a few weeks from now, his subscription will end, and he has no plans on renewing it. So of course this means I'll have to move on to something else. But I don't think I'll find someone who'd be willing to share a... shared host with me again. And besides, the software used on that server is ancient (PHP 4.4.9 + MySQL 4.1.22). There's one obvious solution that comes to mind, I guess: choose a better host and pay for it myself. The problem here is that I have no real fixed income, as I'm only a student. So even if the pricing is dirt cheap, I just can't be certain I will be able to afford it, every single month, for... at least 2 years maybe? So I've looked at free hosting solutions instead. The least requirement I had was that it was completely free of ads. But no matter where I look, I always find something in a corner or two ("what can you expect from a free host?" - yeah I know, but I guess it was worth a shot). For example, on Byethost (one of the free hosts I tried), if you trigger a PHP error while error reporting is set to E_ALL, you will spawn some hidden ad... Besides Byethost, I've tried 000Webhost, x10Hosting, 2Freehosting/1Freehosting, Wink.ws, and they are only worse. Okay, I'm running low on ideas. But! What if I just hosted the site myself, on my own computer? That could work. I actually do have my computer on practically 24/7. But not really. Sometimes I need to reboot it, and sometimes we even have power outages. And what if the hardware needs an upgrade? It's not such a big deal for me if the site went down, because I know what's going on; but what about the users? If I do decide to host it myself, is there some way to show users an alternate page instead of them just seeing a generic "server not found" page in the browser when the site is not accessible? Or is there something I have been missing out on? Is there a different kind of "web hosting" solution out there that I haven't heard of? Here is what I'm really looking for: Free (as in, no costs) NO ads Bandwidth enough for a low-traffic forum with roughly 40 users (Semi-)Up-to-date PHP and MySQL (at least not older than a year) No standard (non-extension) PHP functions turned off - such as sleep() The mbstring extension is enabled Disk space: at least 5 MB At least one MySQL database Some bonus points would be: Max execution time of PHP scripts can be set Remote access to MySQL database What would be the best solution for me? Is there one?

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  • Roll Your Own Solaris Blogroll

    - by Larry Wake
    Something handy I just ran across: There are lots of people here who blog about Solaris, either as their main topic, or as the occasional tangent. If the blogger has tagged their post appropriately, here's a quick way to find them: Articles tagged Solaris Articles tagged ZFS Articles tagged IPS Articles tagged DTrace Articles tagged Zones Articles tagged Studio Articles tagged Cluster Note that this is a little different from using the "word cloud" you can find in the right-hand column on this page, since that only finds articles tagged in this blog. The above links will find all tagged blogs.oracle.com posts. Some topics are a little trickier to nail down, because there may not be a standardized tag for the topic, so building a more conventional "blogroll" is on my to-do list. In the meantime, you can also refer to the post Markus Weber made of interesting Solaris 11 launch-related posts.

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  • How to setup whole-disk encryption with dual boot on a MacBook Pro (generation 9,2 with 12.04)

    - by blueyed
    I can install Ubuntu 12.04 on the MacBook when using the "noapic" kernel boot option, using the alternate amd64+mac image (from http://cdimage.ubuntu.com/releases/12.04/release/ ). But after installation the screen turn sblack after trying to boot "Windows" (as named in the boot menu that shows up when holding Option/Alt during startup). I want to use whole-disk encryption and given that only one free partition is available, I have setup LVM to do so: - vg0 contains bootlv and cryptlv - in cryptlv I have setup encryption with another LVM volume group (vg1, which holds swaplv, rootlv and homelv) I have not installed Grub during installation (because I was not sure about the partition) and when trying to install it later on /dev/sda4 (which contains the outer LVM) it complained that it could not determine the file system, and --force did not help either. The black screen / behavior looks similar to starting the installer without enabling the noapic option.

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  • Pros and Cons of Session Replication

    - by techsjs2012
    Do I really need Session Replication? I am working on a number of web projects for a firm. Most of the projects are about one or two pages of input and then doing a save to a mysql database. Very Basic projects. My SA's are pushing to try to get session replication working in JBoss but I don't really see any need for it and all of its overhead. We need load balancing and clustering so if the server does go down we can move the new requests to the backup service but I am not to big in session replication. This is very low volume projects. In my eyes what is the odds of a user being in the project as the server goes down on the one or two pages. I need to convince the SAs that session replication is an un-necessary complication in this instance. I am looking for pros and cons of session replication so that I can better structure my argument.

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  • Moving OVD from Test to Production

    - by mark.wilcox
    Customer asked support "How to move a test OVD server to production". There is a couple of ways to do this. One way is to clone the environment: http://download.oracle.com/docs/cd/E15523_01/core.1111/e10105/testprod.htm#CH... Another way - which is particularly useful if you want to push configuration from a parent OVD server to children in a cluster: http://download.oracle.com/docs/cd/E14571_01/oid.1111/e10046/basic_server_set... Note if you use the second option and you have any data in a Local Store Adapter - you may also need to use the oidcmprec tool to synchronize that data: http://download.oracle.com/docs/cd/E14571_01/oid.1111/e10029/replic_mng_mon.h... Posted via email from Virtual Identity Dialogue

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  • What are the tactics used to discover what kind of affiliate products will do well in your website?

    - by freethinker
    I'm starting to post some affiliate ads on my website. As it happens, I am not even close to making a sale. I'm not sure if the products I have chosen will appeal to the audience I have. I'm not sure if the volume of traffic is enough to support affiliate programs. I get about 8000-9000 visitors everyday. But since its growing constantly, thats not much of a worry. But I'm surely struggling to figure out what kind of products to market? (its a techie site). Is there a service/tool which can analyze the website and suggest what products will do well and what won't?

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  • Implementing a Custom Coherence PartitionAssignmentStrategy

    - by jpurdy
    A recent A-Team engagement required the development of a custom PartitionAssignmentStrategy (PAS). By way of background, a PAS is an implementation of a Java interface that controls how a Coherence partitioned cache service assigns partitions (primary and backup copies) across the available set of storage-enabled members. While seemingly straightforward, this is actually a very difficult problem to solve. Traditionally, Coherence used a distributed algorithm spread across the cache servers (and as of Coherence 3.7, this is still the default implementation). With the introduction of the PAS interface, the model of operation was changed so that the logic would run solely in the cache service senior member. Obviously, this makes the development of a custom PAS vastly less complex, and in practice does not introduce a significant single point of failure/bottleneck. Note that Coherence ships with a default PAS implementation but it is not used by default. Further, custom PAS implementations are uncommon (this engagement was the first custom implementation that we know of). The particular implementation mentioned above also faced challenges related to managing multiple backup copies but that won't be discussed here. There were a few challenges that arose during design and implementation: Naive algorithms had an unreasonable upper bound of computational cost. There was significant complexity associated with configurations where the member count varied significantly between physical machines. Most of the complexity of a PAS is related to rebalancing, not initial assignment (which is usually fairly simple). A custom PAS may need to solve several problems simultaneously, such as: Ensuring that each member has a similar number of primary and backup partitions (e.g. each member has the same number of primary and backup partitions) Ensuring that each member carries similar responsibility (e.g. the most heavily loaded member has no more than one partition more than the least loaded). Ensuring that each partition is on the same member as a corresponding local resource (e.g. for applications that use partitioning across message queues, to ensure that each partition is collocated with its corresponding message queue). Ensuring that a given member holds no more than a given number of partitions (e.g. no member has more than 10 partitions) Ensuring that backups are placed far enough away from the primaries (e.g. on a different physical machine or a different blade enclosure) Achieving the above goals while ensuring that partition movement is minimized. These objectives can be even more complicated when the topology of the cluster is irregular. For example, if multiple cluster members may exist on each physical machine, then clearly the possibility exists that at certain points (e.g. following a member failure), the number of members on each machine may vary, in certain cases significantly so. Consider the case where there are three physical machines, with 3, 3 and 9 members each (respectively). This introduces complexity since the backups for the 9 members on the the largest machine must be spread across the other 6 members (to ensure placement on different physical machines), preventing an even distribution. For any given problem like this, there are usually reasonable compromises available, but the key point is that objectives may conflict under extreme (but not at all unlikely) circumstances. The most obvious general purpose partition assignment algorithm (possibly the only general purpose one) is to define a scoring function for a given mapping of partitions to members, and then apply that function to each possible permutation, selecting the most optimal permutation. This would result in N! (factorial) evaluations of the scoring function. This is clearly impractical for all but the smallest values of N (e.g. a partition count in the single digits). It's difficult to prove that more efficient general purpose algorithms don't exist, but the key take away from this is that algorithms will tend to either have exorbitant worst case performance or may fail to find optimal solutions (or both) -- it is very important to be able to show that worst case performance is acceptable. This quickly leads to the conclusion that the problem must be further constrained, perhaps by limiting functionality or by using domain-specific optimizations. Unfortunately, it can be very difficult to design these more focused algorithms. In the specific case mentioned, we constrained the solution space to very small clusters (in terms of machine count) with small partition counts and supported exactly two backup copies, and accepted the fact that partition movement could potentially be significant (preferring to solve that issue through brute force). We then used the out-of-the-box PAS implementation as a fallback, delegating to it for configurations that were not supported by our algorithm. Our experience was that the PAS interface is quite usable, but there are intrinsic challenges to designing PAS implementations that should be very carefully evaluated before committing to that approach.

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  • Where is a postgresql 9.1 database stored in ubuntu 12.04?

    - by celenius
    I installed and created a Postgresql database on ubuntu. I then created the database using the following command: sudo su postgres createdb mydatabase However, I can't figure out where the database was initialized. I would like to be able to edit the hba.conf file and postgresl.conf files. When I view the database using pgadmin I see the following information: CREATE DATABASE mydatabase WITH OWNER = postgres ENCODING = 'UTF8' TABLESPACE = pg_default LC_COLLATE = 'en_US.UTF-8' LC_CTYPE = 'en_US.UTF-8' CONNECTION LIMIT = -1; Any thoughts on how I can find the database cluster location?

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