need help with ZFS

[Simun Mikecin]

----- Original Message ----
> From: Mikhail (Plus Plus) <m at plus-plus.su>
> To: freebsd-fs at freebsd.org
> Sent: Thursday, August 27, 2009 11:18:06 AM
> Subject: Re: need help with ZFS
> 
> Last night I installed FreeBSD-8.0BETA3 AMD64, upgraded zpool and zfs, and this 
> morning I did some load on FS to see if it runs more stable now.
> 
> To stress-load the system I ran rsync from ZFS to mounted UFS volume and at the 
> same time I started bonie++ benchmark on ZFS volume:
> 
> bonnie++ -s17000 -d. -n64
> 
> Everything worked fine for about ~90 minutes, but then system paniced. I got 
> escaped to "db> " prompt on local console, but I have zero debugging experience, 
> so I just rebooted the server. The only thing I noticed was that last mentioned 
> PID on the panic screen was bonnie++'s process.
> 
> Also, I'm very confused after re-reading ZFS tuning wiki from here:
> http://wiki.freebsd.org/ZFSTuningGuide
ZFSTuningGuide is sometimes misleading. Better look at /usr/src/UPDATING.

> 
> "amd64
> FreeBSD 7.2+ has improved kernel memory allocation strategy and no tuning may be 
> necessary on systems with more than 2 GB of RAM."
> 
> Does that mean I no longer have to tune ZFS via loader.conf? Just better leave 
> it empty on FreeBSD-8.0 installation?
> 
> Right now I'm going to continue with rsync and will start bonnie++ in parallel 
> keeping my loader.conf with the following values:
> 
> vm.kmem_size="1536M"
> vm.kmem_size_max="3072M"
> vm.pmap.shpgperproc="1024"
> vfs.zfs.arc_min="256M"
> vfs.zfs.arc_max="384M"
> vfs.zfs.vdev.cache.size="50M"
> vfs.zfs.prefetch_disable="1"
> kern.maxproc="20000"

Since FreeBSD 7.2 no additional ZFS tuning in loader.conf is needed (on amd64).
You should remove all those settings from loader.conf, reboot, and re-run the tests.
Maybe, just maybe you get a panic just because of those settings.