One thing I would suggest is using RAD10 instead of RAID5.
RAID5 is frequently a performance bottleneck.
-----Original Message-----
From: xen-users-bounces@xxxxxxxxxxxxxxxxxxx
[mailto:xen-users-bounces@xxxxxxxxxxxxxxxxxxx] On Behalf Of fpt stl
Sent: Thursday, October 06, 2011
12:44 PM
To: xen-users
Subject: [Xen-users] XEN -
networking and performance
I would like some advice from
people how are/were using Xen 3.4.2 - it should be a rather stable
release.
Dom0 is CentOS 5.5 64bit with
Xen 3.4.2 installed with the default settings (minus cpu pinning to Dom0 and
memory setup for 2GB).
There are 2 built-in nics
(Broadcom) and an add-on network card (Intel) with another 4 nics.
Currently only one NIC is used
for all network access, and as far as networking, the default setings are used
- xend-config.sxp:
(network-script network-bridge)
How can I improve the network
performance (now all the VM are sharing one bridge):
a. creating multiple bridges and
assigning a VM (DomU) per bridge
b. trying to hide the NICs from
Dom0 using something like "pciback hide" - (pointers/example of how
one would do this in Centos 5.5 would be highly appreciated...)
Also, I have noticed that
sometimes - somehow erratical since I can not replicate - it seems that VMs are
timing out: while editing in vi it does not respond anymore.
Nothing in the logs, of course.
And no indication in top either. Also, copying 8 GB of data from one disk to
another takes 50 (fifty) minutes !!! - both LVMs attached
separately to the DomU as two independent
volumes [xvda - /dev/mapper/VG1-VM1 and xvdb - /dev/mapper/VG2-VM1_home].
Would it be recommended to have
all the storage in one block device - one xvda only - which will have its own
LVM structure opposed to multiple xvd's?
Any suggestions on improving the
performance in accessing block devices?
I am somehow baffled since
I have read that XEN is used by ISPs which probably host tens of DomUs on a
host machine, and I am struggling to host 7 VMs on a dual quad Xenon box with
48 GB RAM and 3TB RAID5 15K disk storage!
Please be gentle since I am
rather new to XEN.
