[zfs-discuss] Re: Virtualbox VM is unusable on ZFS

Vianney Stroebel vianney at likwid.fr
Sun Apr 1 20:28:38 EDT 2012


You're right. I turned off dedup and it's much better. My Win7 guest
is nearly back to normal speed. Thanks!

I'm still interested in the "ashift=12" property (for those wondering:
http://zfsonlinux.org/faq.html#PerformanceConsideration). Is rsyncing
a zpool to a new one the only way to set this option? Is it worth it?
If so, how do I create a second zpool on a whole disk vdev? ("zpool
create" doesn't seem to work when there's already a zpool).

Also, what partition size is recommended for ZIL and L2ARC on SSD?

Vianney



On Apr 2, 1:45 am, Darik Horn <dajh... at vanadac.com> wrote:
> On Sun, Apr 1, 2012 at 16:46, Vianney Stroebel <vian... at likwid.fr> wrote:
>
> > Host swap goes up about 1 Gb.
> > ...
> > Dedup is ON on the VM filesystem.
>
> 6GB is too small for dedup, especially if the host is already
> swapping.  ZFS write performance severely degrades if the dedup table
> doesn't fit into main memory after everything else is loaded.
>
> --
> Darik Horn <dajh... at vanadac.com>



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