Hi

Ian Turner's comments about the new device API and the possibility of a
retention (not to be confused with re-tension) policy in the dumptype
along with Alexander Jolk's recent comments got me thinking.

With a retention policy by dumptype you would want amanda not to
overwrite a tape if it contained any dumps that need to be retained.
However you might want to add an option to allow amanda to overwrite the
tape if there is enough holding disk space for it to first read all the
dumps that need to be retained off the tape. This obviously is slightly
risky so it would be nice to have Alex's utility that would read dumps
that need to be retained back to a holding disk and then allow the tape
to be overwritten only after these dumps have been put onto another
tape. (It would be nice if the utility could read from one tape and
write to another for those people who have two tape devices but no
holding disk). Amanda could then issue a warning about dumps that need
to be moved in this way in a similar fashion to the way it does now
about level 0 dumps that will be overwritten. 

The retention policy could also be more complicated than just keep for N
days. You could require M level 0 dumps to be kept or a strategy that
would give effectively daily snapshots for the last two weeks, weekly
snapshots for the last two months and monthly snapshots for the last
year. I am not sure how to frame this but I hope you get the idea.

With the ability to move dumps between tapes I wonder if a "changer"
that consist of a number of vtapes and a physical drive might be useful.
Then recent dumps could be on the vtapes and any dumps you want to keep
for longer periods could be migrated to physical tapes. (Can amanda cope
with a changer with more than one tape drive be it physical or virtual?)

I have been playing with vtapes using RAIT with the vtapes being NFS
mounted from an "offsite" (well out of the building) server, so that for
the time we have the tapes in the building there is an out of the
building copy. It would be nice to be able to use a combination of vtape
and physical tapes to extend the time we can keep level 0 backups.

Discussion anyone?


Cheers

Anthony Worrall