Hi,

I have some xen domU on Centos 5.2 server. For some weeks i had a problem with "xen domU" performances. Indeed my xen domU spend a lot of time in cpu waiting.

Reading some informations on the net it seems to come ith I/O heavy load. Using collectd in my domU to monitor the "traffic" on virtual disk and virtuel network i don't see heavy I/O rates.

Thinking my dom0 was overloaded by my domUs i have stopped all my domUs except one but the problem persist. I don't know how to get more informations in order to solve my problem.

For information our config is : - Hitachi SAN infrastructure - DELL 1950 servers with 2 qlogic hba adapters (we used qla2xx drivers and linux dm-multipath for multipathing ) - We have 1 LUN on the SAN for each domU - The dom0 manage theses LUNs using LVM - A domU xen disk configuration looks like this : disk = [ 'phy:/dev/VolGroupIdp/LogVolIdp-disk,xvda1,w'] - In the domU we doesn't use LVM. - At the network level we share a gigabit interface with all the domU using linux bridges. Each bridge refer to a different vlan.

Anyone encoutered I/O performances problems with latests centos 5.2 xen releases ? (In fact i don't really understand if it's a xen problem or a "hardware" problem)

Regards