Re: Disappointing speed with ZFS

On Feb 11, 2008 9:37 PM, Niki Denev <nike_d_at_cytexbg.com> wrote:
> On Feb 11, 2008 7:05 PM, Alexey Tarasov <me_at_lexasoft.ru> wrote:
> > I've done similar tests on the other machine, and all looks fine.
> >
> > But why on this machine ZFS works slower than UFS? When I make UFS
> > file system on the same disk, rtorrent hashing works 10 times faster.
> > And while hashing, HDD is used three times intensively with ZFS
> > (noticed by flashing LED).
> >
> > I have an amd64 Core2Duo processor, 4 Gb of RAM, what is not enough
> > for ZFS?
> >
> > What kernel tuning can help me?
> >
> >
>
> What happens when you disable ZFS prefetching by putting :
>   vfs.zfs.prefetch_disable=1
> in your /boot/loader.conf?
>

This would be my recommendation as well.
I had to disable prefetch to be able to play video files(1.1GB
~43mins) from a 4 disk raidz without jitter. I can even play 2 video
files concurrently now :)
Try and show us the results.



-- 
Joao Barros