[Nottingham] Tape Backup Systems

[Graeme Fowler]

On Fri, 2008-04-11 at 10:45 +0100, Martin Garton wrote:
> I too hate tapes, but one area I think they are better is for off-site
> backups.  Anything being carried off-site has a risk of being dropped,
> and tapes survive this rather better than USB HDD drives in my
> experience.

Quite. Having dropped an old, small IDE drive not too long ago (which
thankfully had nothing on it) and trashed it I can vouch for that one.
Tapes, however, only tend to survive if they're in their polyethylene
box - nice and soft, takes the impact. The ABS that most tape cases are
made from tends to be ever-so-brittle, so will shatter if dropped when
uncased (again, speaking from sad experience).

One thing that's becoming very commonplace now within the enterprise
environment (and I'm sure in smaller places too) is to do your daily
(incremental, differential, whatever) backups across the network to a
"virtual tape library", essentially a big bunch'o'disks attached to the
backup system. Once jobs are completed, another job can be kicked off to
archive those backups (or a single, full backup) to tape by the server.

This has several benefits:

1. Instant restore access in the "Oh c**p, I trashed yesterday's payment
sheet this morning, can you get the tapes out?" scenario.

2. In an optimised environment you can very likely backup multiple
client machines to disk at the same time as writing yesterday's
important stuff to tape.

3. You're very likely to be able to backup clients *and* restore at the
same time, even from tape. No more hanging around waiting for a job to
finish before you put last week's tapes in - simply postpone the write
to tape, change tapes, restore to disk locally on the server and then
restore from there to the client.

Effectively this combines the fast "backup to disk" mentality with the
robustness, storage wise, of "backup to tape". The best (and therefore
the worst also!) of both worlds.

As an additional item, those of you doing regular backups: how often do
you do regular restores, whether driven by necessity (lost data) or to
test your systems? There are one or two NottsLUG parishioners who I know
from a previous job who have been burned by tape failures...

Graeme