RE: [Xen-users] Xen Performance

Robert Dunkley
Tue, 26 May 2009 14:20:06 -0000

Do you have the storage for the Xen VM in a file or in a volume? File based
storage can cache to Ram in Dom0 causing very high disk results.

-----Original Message-----
From: xen-users-bounces@lists.xensource.com
[mailto:xen-users-bounces@lists.xensource.com] On Behalf Of Amir Maqbool Ahmed
Sent: 24 May 2009 11:12
To: xen-users@lists.xensource.com
Subject: [Xen-users] Xen Performance

Hi

I am a student at the University College of Oslo and have in one experiment
tried to test the performance of Xenolinux compared to Native linux on Debian
lenny
2.6.26-2 kernel.

bonnie++ the disk IO bechmark program was used among other tests like cpu
intensive scripts.
The goal is to prove the statement (Once again) that Xen adds only an overhead
of maximum 8%.

The Results of bonnie++ have been surprizing and I want to explain them.
It shows that for some types of Disk IO, like sequential delete and random
create Xen performs faster than native linux. A full comparison chart is
attached as a pdf.
The test are run first from native linux than both from Dom0 and a DomU with the
same results.

Can you please help me understand these results, How can Xenolinux perform
faster although only for some types of operations, then native linux?

Plese forgive me If Im missing something completely obvious.
If you need any further info. please just send me an email and it will be
provided.

Hope to hear from you soon

Amir Ahmed

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