Re: defrag on linux system

From: Peter T. Breuer (ptb_at_oboe.it.uc3m.es)
Date: 09/13/05

  • Next message: Christopher Browne: "Re: defrag on linux system" 
    Date: Tue, 13 Sep 2005 18:38:57 +0200

    Christopher Browne <cbbrowne@acm.org> wrote:
    >> Believe me, 5% of a 4Tbytes RAID causes some raised eyebrows when
    >> discussing volumes... and budgets!

    > Why should this raise eyebrows?

    Well, I would imagine he would want to change it to some constant
    multiple of the largest file size that he will use.

    > 5% of a 4TB RAID represents one 200GB disk drive; perhaps $200 worth
    > of disk space.

    Sure - but 5% is not a magic figure. Provided all his files are small,
    he can get away with a constant number of blocks somewhat bigger than the
    largest file, not a percentage. That is to say, I believe the intention
    is just to keep some free space hanging around in each cluster ("zone")
    in order to deal with allocations with.out having to scavenge for a bit
    here, a bit there, etc.

    If all his files come in one of exactly three sizes, then I would maybe
    keep them on three different filesystems. I don't think there wuld be any
    fragmentation at all then (provided free space per zone was bigger
    than the files, yadda ...).

    Peter

  • Next message: Christopher Browne: "Re: defrag on linux system"

    Relevant Pages

    • btrfs BUG on creating huge sparse file
      ... btrfs seems to tag mostdirty pages with PG_private. ... Below is the kernel messages. ... blocks of free space at or bigger than bytes is ...
      (Linux-Kernel)
    • Re: DD vs normal writing question
      ... ends of files and directories whose lengths are not a multiple of the ... I have Opera configured to erase its cache when it exits, so this stuff becomes accessible to a free space wiper. ... As you hinted above, I do have a collection of files containing passwords and other semi-sensitive items in various formats and encodings and realize that I can't easily sort them out unless I come up with a different way of storing them - a small encrypted partition or an encrypted database would be likely candidates for data that I've created and can control, but I bet there's some sensitive material splattered about in configuration files that I just have to live with. ... martin@ | Martin Gregorie ...
      (uk.comp.os.linux)
    • Re: Entirely unexpected ENOSPC?
      ... Mar 4 01:55:52 vlad kernel: 0 blocks of free space at or bigger than bytes is ... Is there any likely explanation for that behaviour? ...
      (Linux-Kernel)
    • Re: Adding free space
      ... Jack wrote: ... How can I add more free space, keeping every thing I have on it? ... Buy a bigger hard drive. ... Ken Blake - Microsoft MVP Windows: ...
      (microsoft.public.windowsxp.newusers)
    • Entirely unexpected ENOSPC?
      ... Mar 4 01:55:52 vlad kernel: 0 blocks of free space at or bigger than bytes is ... The filesystem was nowhere near full, and I wasn't expecting it to ...
      (Linux-Kernel)