[CentOS-virt] Xen Database vms

Fri Jan 15 17:17:11 UTC 2010
Ben M. <centos at rivint.com>

> I think it could work well. Having a server in a vm makes it
> more portable. 
> Many of my servers and services are running in vms on two
> centos 5.4 servers: openfiler, efw firewall, trixbox 2.8,
> SME Server (in server mode for email and spamassassin),
> windows 2003 server, windows 2008 server, windows 7, and
> others that aren't running.
> I would suggest:
> If there are a lot of temp files or disk access to the OS,
> install the vm OS on a block device rather than to a file.
> The storage should be on a local block device as well. 
> If there's a lot of lan traffic to/from the other vms,
> install a 3rd ethernet card in the server that is only used
> for db traffic. 
> I also use a virtual network that the vms can use to reach
> each other. This is basically a private internal lan running
> across the host machine's buses, rather than through your
> network switch.
> I get native performance with my set up...

Thank you. Excellent thoughts all, and just the type of feedback I
needed to think about. I would be going out a dedicated NIC on the data
traffic, and I would do block devices in LVM for the disk IO, Windows
2008 32bit seems to be very happy with that setup in a mixed Xen
environment. Under no circumstances would I run these as file images. 
There is no comparison to dedicated hardware for this application using 
file based vms. Has to be block devices.

I think for my purposes putting the database servers in Xen is
absolutely worth a shot. If it works, I have a lot of benefits from it.
If it doesn't, I lost some hours but gained some knowledge, and maybe a 
backup server.

A vpn (OpenVPN) server in Xen is part of my plan as well. I'm trying to
sketch out all the lines of IO and see what I have to do to keep things