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Hello, |
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I to have noticed a 'slowing' affect. Naturally I dismissed |
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fragmentation. Is this 'normal' and fixable? |
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|
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On Wed, 2006-02-08 at 11:54 +0100, David Guerizec wrote: |
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> Hello, |
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> |
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> Le Lundi 06 Février 2006 19:50, Duncan a écrit : |
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> > Fragmentation doesn't tend to be as much of an issue on Linux, with "real" |
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> > filesystems, as on MSWormOS, particularly FAT/FAT32. I'm running all |
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> > reiserfs here, FWIW. It doesn't have a compaction tool (defrag, on |
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> > MSWormOS), but I've not noticed any issues as a result. |
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> |
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> Fragmentation seems to be a myth for anyone on Linux, and I was enclined to |
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> believe that myth until I started to use Gentoo. |
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> |
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> At first, a brand new gentoo system is fast, but after a few months and a |
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> dozen emerge -uDN world, things tend to slow down to a point that is barely |
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> acceptable. In fact, the first time I tought that maybe I installed too many |
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> things, and that my system was crippled with cruft. |
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> But then I had to repartition my hard drive, so I made a backup (tar zcvpf) of |
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> my different partitions, fdisk, mkfs, and tar zxvpf. |
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> The system was exactly the same as before, just the partition size had |
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> changed. |
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> But then emerge -S was much faster than before the operation, as well as |
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> common portage operations. |
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> |
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> Since then, I've tried to do the same on several servers, without the fdisk |
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> operation, just tar cp, mkfs, tar xp, and I've always noticed an appreciable |
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> speedup. |
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> |
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> The only explanation that comes from this experiment is fragmentation. |
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> And I think Gentoo is more sensible to fragmentation than binary distributions |
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> because it has to deal with many small files, often changing, during |
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> compilation and rsynchronisation. |
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> |
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> So the directories sensible to fragmentation are IMHO, /var/tmp |
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> and /usr/portage, and they are the ones to put on different partitions. |
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> |
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> Now, I don't have exact numbers to prove my sayings, but anyone can make the |
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> test themself, if they already have /var/tmp and/or /usr/portage on separate |
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> partitions. |
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> |
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> I didn't have time yet to sort out what kind of filesystem is more or less |
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> sensible to fragmentation, but from my experience, ext[23] is not a good |
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> candidate for /var/tmp or /usr/postage. Reiser3 has proven to fragment too, |
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> and one of the last system I installed was formated with XFS, which I will |
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> "defragment" in a few weeks. Hopefully I could then come with numbers. |
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> |
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> BTW, does someone know of a tools to show the fragmentation level of a *nix |
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> filesystem ? |
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> |
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> David |
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> |
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> |
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> |
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> |
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-- |
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Dr Gavin Seddon |
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School of Pharmacy and Pharmaceutical Sciences |
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University of Manchester |
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Oxford Road, Manchester |
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M13 9PL, U.K. |
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-- |
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