Re: [tlug] server partitions, LVM, and Xen

[Micheal Cooper <mcooper@example.com>]

On 2007/05/22, at 16:56, Keith Bawden wrote:
> You could also use have your Virtual Block Device  based on a normal
> physical partition.
>
> Then again I wonder what type of performance hit you would see when
> using a file as Curt suggested. Also, I wonder if a file based
> approach would help simplify things when migrating instances to new
> servers.

This is exactly what I have been wondering about.

At first, I was thinking about having an RHEL5 Xen host with a  
database server in a VM as a file. I started thinking about a VM for  
the database server because it requires PHP4, and RHEL5 uses PHP5.  
Then I realized that I could just copy the file over to another  
machine as a backup for the OS. With daily database dumps and backups  
of the database webapp files, I would have a two-step recovery for  
disasters: 1-copy VM over to Xen host; 2-restore the latest dump file.

A file server would be a harder sell as a VM, but the same principle  
applies: the OS is a single file that is backed up to another machine  
or HDD, but the data would have to live in a partition on the host  
and be backed up (rsync) to a backup server nightly. The restore  
would still be two-part, though. You move the backed-up OS VM file to  
a Xen host and then copy the data from the backup server to a  
partition on the host.

However, I suspect that it is scarier than it seems (and it seems  
kinda scary). Is anyone doing anything like this?