slowdown of zfs (tx->tx)

[Mark Felder]

On Wed, 16 Jan 2013 03:50:09 -0600, Nicolas Rachinsky  
<fbsd-mas-0 at ml.turing-complete.org> wrote:

> * Andriy Gapon <avg at FreeBSD.org> [2013-01-16 11:39 +0200]:
>> on 16/01/2013 02:16 Artem Belevich said the following:
>> > It appears that lots of threads are stuck in
>> > metaslab_activate->space_map_load_wait path.
>>
>> another thing to check - is your pool nearly full.
>
> Don't think so:
> NAME                                 USED  AVAIL  REFER  MOUNTPOINT
> pool1                               5.52T   697G  11.9M  /pool1
>

Never let your ZFS pool go above 80% or you'll have very, very poor  
performance.