On Mon, 2005-12-05 at 12:18, Bryan J. Smith wrote:
> The problem with tape backup is that it's not used
> appropriately. You should never backup directly to tape.
> You should at least buffer to disk. But in reality, why does
> everything have to go to tape in the first place? That's the
> common issue. Stuff like daily backups really don't, and
> even weekly backups are not always required.
My favorite for online disk backups:
http://backuppc.sourceforge.net/
It uses compression and linking of duplicate files to allow
holding much more data than you'd expect so you can keep
some history around.
> At the same time, as much as fixed disk might have an
> advantage in near-guaranteed backups, it does present an
> issue when it comes to long-term retention. The disaster
> recovery schemes I've seen fail are the ones that were either
> all tape-only or all disk-only -- the combination is most
> effective, with disk as the immediate and primary, and tape
> for off-lining longer-term.
>
> Hence the new "killer app" of Virtual Tape Libraries.
> http://www.samag.com/documents/sam0509a/
The free version is to image-copy the backuppc archive
filesystem to an external drive. It's cheaper than a fast
tape drive and you can plug the external disk into a laptop
anywhere for immediate remote restores without needing another
tape drive. The downside has been firewire support on Linux
the way I'm trying to do it, which is to periodically sync
a RAID1 mirror and break it for offsite storage. I had been
hoping to leave the RAID live except for a weekly swap - and
in fact this worked with the 2.4 kernel, but there I had to
do some contortions with modprobe to notice the new drive
and once in a while it would take a reboot. With 2.6 based
kernels the hotswap is usually noticed correctly, but with
some versions leaving the RAID active causes a crash and
others the drive is kicked out in a few hours. It does work
just well enough to do complete a sync when backups aren't
running so I'm putting up with the problems for now.
I suppose I could unmount the internal disk and use dd to
copy for the same effect.
--
Les Mikesell
lesmikesell@xxxxxxxxx
