[j-nsp] Steel-Belted RADIUS backups

[Michael Loftis]

On Aug 30, 2013 1:46 AM, "Jed Laundry" <jlaundry at jlaundry.com> wrote:
>
> If it's Linux, are you using LVM as a storage layer?
>
> LVM snapshots are your friend for making a consistent backup, regardless
of
> if you use a tar script or VM snapshot/image.

Unless developers have made major structural changes to LVM snapshots
they're nearly useless. They require large swaths of contiguous kernel RAM
for the CoW bitmap so once a machine is running for a while and thus has
fragmented its RAM free space you end up with LVM bailing out while trying
to snapshot.  The other side of that is if your snapshot routine doesn't
shutdown services and unmount the filesystem you're essentially
snapshotting a crashed server and hoping filesystem and database recovery
goes well when you restore that "backup"

>
> Thanks,
> Jed.
>