8.1 amd64 lockup (maybe zfs or disk related)

[Tom Evans]

On Tue, Feb 8, 2011 at 2:52 PM, Patrick M. Hausen <hausen at punkt.de> wrote:
> Hello, Jeremy,
>
> Am 07.02.2011 um 09:55 schrieb Jeremy Chadwick:
>> The Wiki is outdated, I'm sorry to say.  Given that you have 8GB RAM, I
>> would recommend these settings.
>> ...
>
> Thank you very much for the insight. A current summary of recommended
> settings is very much appreciated.
>
> Could you add values for amd64 machines with 4 and 16 GB of memory?
> That would help me a lot. Storage around 4 and 11 TB, respectively.
> Access pattern: backup storage.
>
> Kind regards,
> Patrick

My home file server is similar in spec to that - Core 2 Duo, 4 GB RAM
and running 8.2-RC3/amd64, with a pool with two 6 x 1.5 TB raidz
arrays, for a total capacity of ~16 TB. The only ZFS settings I have
changed from default are:

# Allow prefetch (normally disabled for 4GB or less RAM)
vfs.zfs.prefetch_disable=0
# Don't let ZFS use UMA, restricts available memory
vfs.zfs.zio.use_uma=0

I think vfs.zfs.zio.use_uma defaults to 0 now anyway.

I've never had a crash related to memory pressure or any other ZFS
issue - it doesn't get that stressed. YMMV!

Cheers

Tom