Rule of thumb: When to replace tape media?

[TopRung]

I know there is much room for variance here, but as a rule of thumb, how long do you think tapes should remain in rotation - to avoid the wear-and-tear.


Thank you

 

[robmcl]

You didn't mention what type of tapes you're using, but I'll assume that in this forum we're talking about some flavor of DLT. The manufac claims that DLT is "supposed" to be rated for 500,000 passes (take that as you will...).

For my DLTs used on a daily basis, I'm comfortable leaving them in the rotation for at least 1 year. It certainly depends on your scenario. If you're doing a "full" system backup everynight then you can afford to have one tape go bad and you're only one day behind. If you do incrementals and you lose one tape, the whole set is toast...again it depends.
(Of course, this comes from a guy who been around long enough to have done full system backups on multiple 4mm-DAT audio tapes. The manufac specs on those were rated for 15 passes (that's "fifteen&quot but we used them day-in and day-out for months at a time ha..ha..ha... life on the edge...<grin>

HTH...Rob

 

[TopRung]

Man, sorry for the lack of info - I got ahead of myself.

We use Sony 150P 20/40GB DDS4 tapes. Nothing fancy as far as our scheme/hardware, and we do a full backup every night. One tape/month is taken off premises permanantly. We have been using the tapes since 05/2003.

So, I was going to order 40 new tapes and change the backup scheme to a "Grandfather" scheme as Veritas notes in their manual; using differentials and so on. But the more I read, the more I see scarey scenarios with differentials. Hmmmm. What to do????