ZFSKnownProblems - needs revision?
ben at wanderview.com
Mon Apr 13 02:43:28 UTC 2009
On Apr 8, 2009, at 12:18 PM, Christian Walther wrote:
> I used geli encrypted ZFS including Root on my IBM Thinkpad T31 with
> 1GB RAM on a 160GB HDD. (i386 7-STABLE)
> Swap on a dedicated slice. Some Z Filesystems used compression
> (/usr/ports, /usr/src, for example).
> I encountered several crashes, especially during heavy loads, such as
> compiling big ports.
Can you clarify what you mean by "crashes"?
I have a very similar system here using zfs on geli with compression
on a non-SMP i386 machine. The only real difference is that I am
running 8-CURRENT. With this setup I've found that I can reliably get
the system to go into livelock under load. I posted some analysis and
a possible patch in this thread:
I'm still investigating what exactly triggers the problem, but it
appears that if the ARC cache comes under memory pressure at the wrong
time certain zfs transaction threads can enter an interlocked looping
pattern. Without proper thread prioritization this can prevent the
system from writing data out and thus keep the loop running forever.
You can find a better copy of the patch here:
I intend to update this with some tweaked priority values, but this
should still work fine.
Please note, however, that at least one person encountered a panic
when they tried this patch. Its not clear if this was due to the
thread priority changes interacting with their zfs-on-root
configuration or if it was unrelated 8-CURRENT changes. Also, I have
not tested the patch against 7-STABLE. I'd be interested to know if
it helps with your systems (although it sounds like you abandoned zfs
Anyway, I hope that helps.
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