Re: [Qemu-devel] [PATCH] This patch adds a new block driver : iSCSI

[ronnie sahlberg]

On Thu, Sep 15, 2011 at 7:11 PM, Paolo Bonzini <address@hidden> wrote:
...
> Perhaps Ronnie has rough performance numbers comparing in-kernel iSCSI with
> libiscsi?

I did some tests some time ago just doing things like 'dd if=/dev/sda
of=/dev/null' on the root disk from within a RHEL guest itself
and performace was comparable.
In some tests libiscsi was a few percent faster, in other tests it was
a few percent slower.
But overall, very unscientifically performed test, performance was not
much different.

Now, I am not an expert on tuning cache or tuning the kernel scsi and
iscsi layer, so I would not really want to make too many statements in
the area other than in some tests I performed, performance was good
enough for my use.


I would be very happy if someone competent in tuning
qemu/scsi/open-iscsi (==that means, not me) would do a real
comparasion.


regards
ronnie sahlberg