Date: Thu, 20 Dec 2007 19:41:09 +0300 From: dima <_pppp@mail.ru> To: Alexandre Biancalana <biancalana@gmail.com> Cc: freebsd-performance@freebsd.org, Mike Tancsa <mike@sentex.net> Subject: Re[2]: Bad performance when accessing a lot of small files Message-ID: <E1J5OSL-000Fl1-00._pppp-mail-ru@f156.mail.ru> In-Reply-To: <8e10486b0712191207r5e256b84xf6cb0bbafc6cfd20@mail.gmail.com> References: <8e10486b0712191207r5e256b84xf6cb0bbafc6cfd20@mail.gmail.com>
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>>>The behavior that I'm observing and that want your help is when the >>>system is accessing some directory with many small files ( directories >>>with ~ 1 million of ~30kb files), the performance is very poor. >> >> Hi, > > I'm using zfs, I think this change the things.. no ? > > > Have you adjusted the dirhash value ? What does > > > > sysctl -a vfs.ufs | grep dirhash > > # sysctl -a vfs.ufs | grep dirhash > vfs.ufs.dirhash_docheck: 0 > vfs.ufs.dirhash_mem: 1410338 > vfs.ufs.dirhash_maxmem: 2097152 > vfs.ufs.dirhash_minsize: 2560 I agree with Mike. Try to run this command while listing your large directory. You'll see that dirhash_mem will reach dirhash_maxmem. So, the value of dirhash_maxmem should be increased. One more hint. Mounting filesystems with -noatime option greatly improves read performance. Apply this also, if you haven't done this yet.
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