On 08/15/2011 10:51 PM, Nico Kadel-Garcia wrote:
On Mon, Aug 15, 2011 at 6:05 PM, Orion Poplawski<[email protected]> wrote:
I have a server that I recently migrated from CentOS 5.6 to SL6.1. The host
install serves as a basic disk server and runs our nightly backups with
amanda. We also have several virtual machines running on it, so of which
are mostly idle and others which can be quite busy. Since making the move
I'm seeing the disk and network response/performance go to hell if I have
any non-idle VMs running. One barometer - I have a raid10 rebuild running
at the moment. With no VMs I can reach 200,000K/sec resync speed. I'm
getting 131,000K with two idle VMs and some other basic activity. If I
start a busy vm, it drops to a few hundred K/sec and all disk access is very
slow. Response to keystrokes in a network shell can be very slow as well.
As anyone else experienced problems like this? I'm not seeing any error
messages on the host or VMs.
Have you rebuilt the virtual images? And does the underlying RAID, and
the disks, have 4096 byte blocks? If so, you will need to be quite
cautious in partitioning your disk images, because no installer in the
world can tell from scratch, inside a virtualized host, what the block
size is on the underlying hardware, and this can *kill* your
performance if it's mis-set.
Nope, everything is as before - I installed SL6 into the existing volume group
and preserved the VMs logical volumes. Thanks for the heads up though.
--
Orion Poplawski
Technical Manager 303-415-9701 x222
NWRA/CoRA Division FAX: 303-415-9702
3380 Mitchell Lane [email protected]
Boulder, CO 80301 http://www.cora.nwra.com
