Hello Joel!
Wow! This is really a big surprise to me. I can conclude that i can't guarantee several days of backup, but just the last one (or at most the last 2) ?
You can certainly guarantee several days of backup, not only the last 1 or 2. How many days exactly, depends on how you have set your dumpcycle, tapecycle and runspercycle. As I already wrote, you need to set these according to your recovery needs.
For example, consider dumpcycle of 7 days, runspercycle of 5 and tapecycle of 20 tapes. In worst case, you will have 4 oldest incremental backups of some DLE where the full that they are based on no longer exists. This being the case, the oldest level 0 is 22 days (16 tapes) old and you have a total of 4 full backups of this DLE.
It is true that you won't have full backups of every DLE from 28 days (20 tapes) ago. I can't see how this would be possible with Amanda's scheduling, unless you configure Amanda to do full backups only. Most of us don't have enough resources to do that...
-- Toomas Aas
