7.0-Beta 3: zfs makes system reboot
Michael Rebele
m.rebele at web.de
Fri Dec 14 07:11:27 PST 2007
Hello,
replying my own message is a funny thing ;-)
This message has more informational character than it is a error report.
> Michael Rebele <m.rebele at web.de> wrote:
> Von: m.rebele at web.de
> Gesendet: 03.12.07 15:54:59
> An: freebsd-current at freebsd.org
> Betreff: Re: 7.0-Beta 3: zfs makes system reboot
>
> Alexandre Biancalana wrote:
> > On Nov 30, 2007 2:27 PM, Michael Rebele <m.rebele at web.de> wrote:
> >> 4. The applied kernel settings
> >> kern.maxvnodes="400000"
> >> vm.kmem_size_max="512M"
> >> vm.kmem_size="512M"
> >>
> >> 5. Output from zpool
> >> [root at zfs /root]# zpool status
> >> pool: tank
> >> state: ONLINE
> >> scrub: none requested
> >> config:
> >>
> >> NAME STATE READ WRITE CKSUM
> >> tank ONLINE 0 0 0
> >> ad4s1g ONLINE 0 0 0
> >>
> >> errors: No known data errors
> >>
> >> [kmem_map too small error]
> >
> > Have you tried this patch
> > http://people.freebsd.org/~pjd/patches/vm_kern.c.2.patch ?
>
I've applied the mentioned patch to the Beta3. Now the iozone-Benchmark
runs through. Fine - be warned, on my machine it took about 30 hours (a
3GHz DualCore and a 160GB SATA HD w. 10000rpm).
After the first successful run on a ZFS since my first try i tried the
next step.
Three parallel iozone (for your reference, here's again the setup:
iozone -R -a -z -b filez-512M.wks -g 4G -f testile) runs on the
mentioned machine. Nearly 5 days everything went fine, but then the
system made a reboot. Unfortunately there's no log and the reboot
happened in the night. Though, i don't really know the reason for this.
I guess, the kmem_map error is the cause, because the symptoms are the
same as on the BETA3-system before the applied patch. The last output i
have from the benchmark, showed that the file size were in the 4GB area
with a reclen in the 8192 area (well, short before iozone should finish).
The problem is to track down the stuff, as it may took quite long until
the error occurs - or lets say it better, even on a quite fast machine,
iozone is quite slow. But the problem is not the CPU, it's the HD. Maybe
somebody with access to a fast HD-Array can investigate this again.
My conclusions to my tests:
1. You should really apply the mentioned patch if you plan to use ZFS on
your Box for more than just testing and experimenting (well, ZFS is
marked as that, though - you're warned). The memory/kernel parameter
tuning recommendations helped me not really.
2. With the applied patch, ZFS seems quite robust for the average use.
Maybe, there's a problem with a bigger load under some (rare?)
circumstances.
3. The patch should find his way to the 'regular' kernel sources (or is
it even in BETA4?).
A big thanks to Pawel Jakub Dawidek for his great job.
Michael
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