log not working?

Kate Ward kate.ward at forestent.com
Sun May 1 17:04:57 EDT 2011


It looks like your log device is pretty large (55.5G). According to the ZFS
Evil Tuning Guide (
http://www.solarisinternals.com/wiki/index.php/ZFS_Evil_Tuning_Guide#Disabling_the_ZIL_.28Don.27t.29
),

The size of the separate log device may be quite small. A rule of thumb is
that you should size the separate log to be able to handle 10 seconds of
your expected synchronous write workload. It would be rare to need more than
100 MB in a separate log device, but the separate log must be at least 64
MB.


You might want to partition that drive into a small 1G or 2G partition, and
use the second for caching data.

- kate

On Mon, Apr 11, 2011 at 3:11 AM, Ned Bass <nedbass at gmail.com> wrote:

> The ZIL is only used for synchronous writes.  From the fio man page it
> looks like you can use --sync=true to test this out.
>
> Ned
>
> 2011/4/10 sozo1976 <sozo1976 at gmail.com>:
> > wrong copy from the zpool iostat on last post. correct one:
> >
> >               capacity     operations    bandwidth
> > pool        alloc   free   read  write   read  write
> > ----------  -----  -----  -----  -----  -----  -----
> > tank        13.1G  9.05T     26  3.81K   158K   469M
> >  raidz1    13.1G  9.05T     26  3.81K   158K   469M
> >    sdb         -      -      1    945   107K   112M
> >    sdc         -      -      1    993   107K   118M
> >    sdd         -      -      1    949  85.3K   113M
> >    sde         -      -      1    951  85.3K   113M
> >    sdf         -      -      1    958   107K   114M
> >  sdg           0  55.5G      0      0      0      0
> > ----------  -----  -----  -----  -----  -----  -----
> >
>



-- 
Kate Ward <kate.ward at forestent.com>
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