Slow/locking UFS/VFS in 6.1?
pmurray at nevada.net.nz
Tue Sep 5 20:40:43 PDT 2006
I just upgraded a webserver (serving a pretty busy site) from a Dual
Xeon 2.4Ghz with a 3Ware 7850 8-port (8x Seagate 120GB IDE drives in
RAID5) running FreeBSD 4.11 to a Dual Opteron 248 with a 3Ware
9550SX-8LP (8x Hitachi SATA2 250GB drives in a RAID5) running FreeBSD
The site runs considerably slower on the faster machine running 6.1,
things seem to be blocking on IO a lot more. For instance a page
could load very quickly from Apache, and if you reload straight away
it can take up to 20 seconds for the page to load again.
When this happens it seems a lot of Apache processes get stuck in the
UFS state (in top).
Is there a way to debug what's going on? or work around it. It should
be much much faster which the faster disks and raid controller. Is
this lock contention in VFS?
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