System crawls after Upgrade 7.0->7.2

Tobias Lott tlott at
Tue Sep 8 10:39:23 UTC 2009

Hey Everyone,

I upgraded a Dual Core Machine to 7.2-Stable (2 Days ago), all OS
related Stuff is located on an UFS Slice, Application is on a ZFS

After the Upgrade everything seemed fine, but a User noticed one PHP
Script which is basically loading a plain Textfile into Mysql times out.
PHP Timeout was set to 60 secs, that was more then enough just one day
before the upgrade.

System-wise its like Mysql can't get get the data fast enough, process
is max at 10% cpu usage most of the time in sbwait state.

Haven't changed any sysctl (kern.maxvnodes="200000", vm.kmem_size="512M"
vm.kmem_size_max="512M" vfs.zfs.arc_max="100M" but had those before
already) or kernel parameter at that time. But according to the Wiki's
ZFS Tuning Guide those aren't needed anymore so I tried without but no
change there either.

I checked the following (and the current used values each):

Getting no error messages dmesg, syslog wise.

Tried moving Mysql to the UFS Slice but same thing happens happens

Some very basic testing like dd-ing:
# dd if=/dev/da0 of=/dev/null bs=1024 count=1048576
1048576+0 records in
1048576+0 records out
1073741824 bytes transferred in 157.698602 secs (6808823 bytes/sec)

FreeBSD hostname 7.2-STABLE FreeBSD 7.2-STABLE #3 r196954:
Tue Sep  8 02:10:22 CEST 2009
root at hostname:/usr/obj/usr/src/sys/SPIRIT  amd64

Since I upgraded the Machines zpool to version 13 already I don't
really wanna go back to 7.0, but it seems the only way out atm.

Hopefully someone can give me a Hint where maybe I forgot to check.

Somehow it feels like the last Versions, I'd say starting with 7.x
doesn't really feel that Rock-Stable as Versions Prior used to
be. Prolly cause I'm using an Experimental Feature like ZFS, so no
Offense nor Blame and this is not intended as a Flame or whatsoever!
So don't get me wrong, I always liked, used, recommended FreeBSD since
4.0 and will continue to do so!

Best Regards

Tobias Lott

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