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Patrick R
Asked: 2010-08-06 11:11:15 +0800 CST

ubuntu cluster - so close but so far

  • 772

Here's the set up:

  • Two Ubuntu 9.10 servers - LAMP environment (not really an option to switch OS)
  • One MD3000i with iscsi connection

Here's what I'd like to do:

  • Have both server see the files that the other one writes to the MD3000i without unmounting the drive. My connections are fine to the MD3000i (using open-iscsi). The MD3000i is great in almost every way I need except for one listed below.

Here's what I don't want to do (for reasons I'm not going to go into - been down this road already):

  • Use NFS mounts

Example:

  • Server1.com and Server2.com write to the same drive on the MD3000i. The folder that they are both mounted to is labeled /mnt/files/. They both recognize the partition size correctly.

    Then Server1.com writes test1.1.txt to /mnt/files and Server2.com writes test1.2.txt to /mnt/files. Files are written during ssh connections directly on server in this situation. Server1.com does not see test1.2.txt without remount. Server2.com does not see test1.1.txt without remount.

    Oddly, if I write the files from an apache server via PHP and the file has a unique name, both server's see it! But if the name is not unique I then have an I/O error (no surprise).

    I'm familiar with gfs, gfs2 and ocfs2 but far from competent. I've tried various methods for formatting the drive and mounting it. It seems as though I just can not get the recipe correct.

Question:

What are your suggestions? I've tried many different ways to set up what I'm been lead to believe is the holy grail - clustering - with no real success. I know what doesn't work. Could really really use a boost from some helpful tips.

ubuntu cluster gfs ocfs2 gfs2

2 Answers

  1. Best Answer

    Short answer : GlusterFS

    Long Answer: I have set up a system with DRDB which I thought would be the ideal solution as it is well documented and loads of examples can be found of running LAMP on it.

    But it isn't the ideal solution as you only have the file system mounted on one box at a time and you have to handle a lot of services starting etc when one machine fails over to the other. Also it is only for two machines.

    I built a test glusterfs cluster of two virtual Ubuntu Lucid Lynx machines in virtualbox today and not only is it ridiculously easy to set up, everything you need is in the repos.

    From my tests so far it appears to be everything I want.

    It is a bit like a two way (or actually multiway) nfs. You can have as many nodes as you want accessing it and the file system handles the locks etc, so ignore the "This is a bad idea, like having 2 concurrent windows installations accessing the same NTFS drive..." comment above, because that is way off course.

    Make sure you get the server - client aspect of it! I missed the point of the FUSE mount until I considered the file locking.

    I have yet to test it under heavy MySQL load but so far I am impressed. My web searches had found very little to suggest GlusterFS is up to the job so I am reassured by Tom O'Conner comment too.

    If I find any more relevant information tomorrow I will post back.

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  2. Ok ... you excluded NFS. something similar could be AFS.

    Or you could also try sshfs.

    I don't know if they solve your problems, but they it's good to have them in mind :>

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