zpool - low speed write

[Artem Belevich]

On Wed, Aug 4, 2010 at 9:47 PM, Alex V. Petrov <alexvpetrov at gmail.com> wrote:
...
>> > vfs.zfs.cache_flush_disable=1
>> > vfs.zfs.zil_disable=1
>>
>> I question both of these settings, especially the latter.  Please remove
>> them both and re-test your write performance.
>
> I removed all settings of zfs.
> Now it default.
>

ZFS would throttle writes if it thinks that not enough memory is
available. Did you by any chance tinker with VM parameters, too? Could
you post output of following commands?

sysctl vm |grep kmem
sysctl vfs.zfs
sysctl kstat.zfs  (before and after after you do some of your write speed tests)

--Artem