[ILUG] Cheap tape drives

[Philip Reynolds]

Eoin Phillips's [eoinp-ilug at celt.dias.ie] 20 lines of wisdom included:
> The backup will be done weekly (incremental) and monthly (full) for a 10GB
> partition.  This means seven tapes at £12 each I think, plus £129 for the
> drive itself.  Does this sound like reasonable value for money to others?
> Also, I wasn't able to find out how many times the tapes can be reused.
> Are Travan tapes especially delicate?

I won't comment on your tape drive as I have little to no experience
with your drive of choice.

However your backup schema seems relatively naive and could cost you
quite a bit of hassle if data goes lost. It could be rearranged to
implement a "better" backup system, if data needs to be recovered.

Implement a full backup on a Friday evening. If you choose your
backup media appropiately, that should fit on one tape. (believe me,
the last thing you wanna do on a Friday evening is sit until one
backup finishes, because you have to change the tape)

After this, I would recommend a differential backup (incremental is
a pain in the ass if you have to restore, and you don't have a lot
of disk-space being used) every day of the week. Therefore restoring
a backup of Wednesday, means restoring the tape for the Friday
before, plus Wednesday's differential backup. (Incremental means
restoring Friday, Monday, Tuesday and then Wednesday)

Therefore, what you need is some sort of grandfathered setup to the
backup system.

Take 4 tapes. (Label them Monday to Thursday)
Take 4 more tapes (Label them A-D or 1-4 or whatever).
Use a system for labeling the tapes (and maybe recording them on
paper) by date.

This way, you have eight tapes, which can restore up to a month ago.

You can restore the last weeks worth of data, plus 4 weeks worth of
full backups.

(This is called granfathering, and if you want a more comprehensive
scheme, you can do this by months or years etc.)

Phil.