Your system looks pretty slick, although what's the restore operation look like? At the end of it... do you havehalfgaar wrote:Probably when they say it's not a long term solution, they mean live copy-on-write snapshots, and retaining them. That's true, because all write operations then have to be duplicated.I looked at snapshots, but saw a few comments that
snapshots were not a suitable long term backup mechanism.
My system is basically what you have, but then without downtime, and more efficient because it doesn't store unused blocks from the file system. I use Xen and my disks are on LVM (logical volume management). With LVM, you can make in instant copy-on-write frozen snapshot of any volume. So, my scripts, in essence:
* Make a snapshot
* Take the first 100 MB and dd it: that will contain partition table and boot loaders.
* use losetup to scan for partitions on it.
* Do a filesystem repair, because it 'looks' like a uncleanly shutdown file system
* Use partclone on a designated partition in the snapshot, to only copy the used blocks to a gzip file
* Delete the snapshot
to piece together the GZIP files which contain sets of used blocks?
I normally use LVM, but for some reason this particular server does not have LVM. Not sure why.
Your comment about the snapshots looking unclean is something I ran across. I initially paused
the VM before copying, and of course that always needed a repair before restore. I was worried about
whether those repairs were guaranteed to succeed, so I elected to switch to shutdown where I had a
guaranteed clean FS. Sadly - I now get occasional restart issues .
Thanks for the insights.
Paul.