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[Xen-users] Disk performance under Xen

To: "xen-users@xxxxxxxxxxxxxxxxxxx" <xen-users@xxxxxxxxxxxxxxxxxxx>
Subject: [Xen-users] Disk performance under Xen
From: Gavin Conway <gavin.conway@xxxxxxxxxxxxxxxxx>
Date: Fri, 31 Jul 2009 11:32:53 +0100
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Thread-topic: Disk performance under Xen
Hi All,

We're seeing some really poor disk performance under Xen Source. Below are the 
output of some Bonnie++ tests ran on the underlying host as well as on a HVM 
instance. We've seen the same level of performance on Debian Etch and Debian 
Lenny. Can anyone comment on what we might do to improve this and get 
near-native performance from a HVM machine.

Host - Running Centos 5.3

Version  1.03       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
tig-xen-host-1. 14G           212037  38 115111  19           300545  12 779.4

Write: 207MB/s
Rewrite: 112MB/s
Read: 293.5MB/s

Guest host - running Centos 5.3

Version  1.03       ------Sequential Output------ --Sequential Input- --Random-
                    -Per Chr- --Block-- -Rewrite- -Per Chr- --Block-- --Seeks--
Machine        Size K/sec %CP K/sec %CP K/sec %CP K/sec %CP K/sec %CP  /sec %CP
localhost.locald 2G           29566   4 21399   5           88812   9 497.7   6

Write speed: 28.87MB/s
Rewrite speed: 20.89MB/s
Read: 86.73MB/s


Gavin Conway
Senior Engineer, Operations (Systems Group), UKSolutions

Telephone: 0845 004 1333, option 2
Email: gavin.conway@xxxxxxxxxxxxxxxxx
Web: http://www.uksolutions.co.uk/
UKS Ltd, Birmingham Road, Studley, Warwickshire, B80 7BG Registered in England 
Number 3036806
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