Re: [Xen-users] Xen Performance

Javier Guerra
Tue, 26 May 2009 14:29:05 -0000

On Sun, May 24, 2009 at 5:12 AM, Amir Maqbool Ahmed
<AmirM.Ahmed@stud.iu.hio.no> wrote:
> It shows that for some types of Disk IO, like sequential delete and random
create
> Xen performs faster than native linux.

let me guess: you''re running your DomU''s images as files, and
the
bonnie++ testsize is bigger than DomU''s RAM, but less than
Dom0''s RAM.
 right?

it''s an illusion created by the file-level caching at Dom0.  try
bigger a testsize and it should disappear.  in fact, with real-life
loads it''s the slowest config, with better performance when you use
lower-level backends (LVM, or tap:) that skip the cache.

--
Javier