Le 12/12/2011 03:00, Xupeng Yun a écrit :
On Mon, Dec 12, 2011 at 09:00, Dave Chinner <david@xxxxxxxxxxxxx
Oh, of course, now I remember what the problem is - it's a locking
issue that was fixed in 3.0.11, 3.1.5 and 3.2-rc1.
Got it, thanks.
xfs mailing list
I'm seeing more or less the same here.
Generally speaking XFS code in recent kernels seems to decrease CPU
usage and be faster, which is a very good thing (good works, guy). But...
On two particular server, with recent kernels, I experience a much
higher load than expected, but it's very hard to tell what's wrong. The
system seems more in I/O wait. Older kernels (2.6.32.xx and 2.6.26.xx)
gives better results.
Following this thread, I thought I have the same problems, but it's
probably not the case, as I have tested 2.6.38.xx, 3.0.13, 3.1.5 with
Thoses servers are mail (dovecot) servers, with lots of simultaneous
imap clients (5000+) an lots of simultaneous message delivery.
These are linux-vservers, on top of LVM volumes. The storage is SAN with
15k RPM SAS drives (and battery backup).
I know barriers were disabled in older kernels, so with recents kernels,
XFS volumes were mounted with nobarrier.
As those servers are critical for us, I can't really test, hardly give
you more precise numbers, and I don't know how to accurately reproduce
this platform to test what's wrong. I know this is NOT a precise bug
report and it won't help much.
All I can say IS :
- read operations seems no slower with recent kernels, backups take
approximatively the same time ;
- I'd say (but I have no proof) that delivery of new mails takes more
time and is more synchronous than before, like nobarrier have no effect.
Does this ring a bell to some of you ?
Yann Dupont - Service IRTS, DSI Université de Nantes
Tel : 02.53.48.49.20 - Mail/Jabber : Yann.Dupont@xxxxxxxxxxxxxx