[ILUG] Cheap tape drives

[Rick Moen]

Quoting Eoin Phillips (eoinp-ilug at celt.dias.ie):

> I'm in charge of a small server (20GB) used for Samba, and it's high
> time we put a proper backup scheme in place!  There's not a lot of
> money for this and I don't want to go to SCSI unless necessary (we
> currently have a UDMA 100 card), so I was thinking of going for a
> Seagate internal IDE drive, using Travan tapes (4/8GB).  Has anyone
> any experience of these?

They seem inexpensive, but they aren't, because the tapes cost too much.

> The backup will be done weekly (incremental) and monthly (full) for a
> 10GB partition. 

First of all, do differential instead of incremental.  (A differential 
backup is one of all changes to date, relative to the last full backup.)
This avoids the first few incremental tapes being single points of
failure for restores.  

Second, you need to plan on retiring the differential (or incremental)
tapes and replacing them on an occasional basis, because they will wear
out.  And I personally think you should keep the monthly backup for at
least several months before overwriting them, and I would urge a full
year.

Third, I'd do differential tapes every _weeknight_ (M-Th), and full
backups every Friday night.  So, you'll have five Friday tapes in
service, at any given time (plus four daily ones).

I say daily because you'll be kicking yourself if you ever lose most of
a week's worth of work, despite functional backup.

So, for the daily tapes, you might (as a wild guess) need four sets of
four tapes for a year.  As you say, they wear.  And then thirteen
Friday tapes for the first year, because you remove one from rotation
every month as the monthly archival tape.  But then no new Friday tapes
for the second and later years, because you're rotating the prior year's
back in as they become over a year old (but a new set of sixteen daily
tapes per year).  And those weekly tapes will probably last until the 
drive is obsolete.

Given the cost of media, then, I'd say DDS3, not Travan.
http://kmself.home.netcom.com/Linux/FAQs/backups.html

Don't forget to buy and use cleaning tapes.

-- 
Cheers,        "Linux means never having to delete your love mail."
Rick Moen                                              -- Don Marti
rick at linuxmafia.com