Re: [Xen-users] Re: How to Backup and Restore MBR within Logical Volumes?

On Thu, Nov 12, 2009 at 5:10 PM, Mr. Teo En Ming (Zhang Enming)

<space.time.universe@xxxxxxxxx> wrote:

> Hi,
>
> I don't think I will be using the LVM snapshot method. I will simply ensure
> that my domU is not running,

Ah, so you can live with the down time. It makes things a lot simpler then.

> then I proceed to do the losetup and kpartx
> procedure.

Like others mentioned, you don't need losetup for LVs. It will only
make things slower.

> Subsequently I will backup the MBR of my domU by dd-ing
> /dev/loopX and clone all the filesystems of the domU using fsarchiver.
>
> I would like to use fsarchiver because it can support LZMA compression. LZMA
> can compress better than bzip2 and decompress 3x faster than bzip2.
> partimage only supports gzip and bzip2.

If your concern is the size and speed of backup, here's one final note
from me: you might want to look at zfs. Possible use scenarios :
- use opensolaris as dom0. Probably the most supported option when it
comes to xen + zfs, but you need to be familiar with how opensolaris
works.
- use external storage server running solaris/opensolaris as iscsi
SAN. Think of it as poor-man's Netapp.
- use zfs-fuse inside Linux dom0, and store domU storage as files
- use zfs-fuse on domU, and do backup from domU instead of dom0.

With zfs, you'd get zfs snapshot (which is like instaneous in-place
backup), incremental block-level send (can greatly reduce backup
storage size if your data doesn't change often), optional transparent
compression for live data (like what ntfs has).

--
Fajar