Do any of the available backup solutions support a "dump to disk mode" like amanda? Amanda uses the disk on the local backup machine as the cache. After the backup completes to disk amanda dumps that file to tape. This takes care of the streaming issues. This of course would be a problem with large NetApp filesystems. But imagine if the packages (veritas, legato, workstation solutions, etc.) took the incoming data stream and wrote it as configurable chunks (100Mb, 1GB, etc.) to disk. They could then flush those chunks to tape.
barry
We're doing something similar to this. We are backing up to an ADSM server with a HSM filesystem. This filesystem is stored on a tape robot with a disk cache. As files are created on disk they are migrated to the tape robot and replaced on the disk with a "stub" file. To the user it just looks like a very large (but slow) filesystem. If you try to access a file that is migrated to tape, your process suspends while the robot stages the file back to disk.
So we are running our dumps from the ADSM server more or less like this:
cd /dumps/netapp/`date %Y.%m.%d` rsh netapp dump 0uf - /vol/vol0 | split -b 1024m - dump.
split breaks the dump into 1G files named dump.aa dump.ab ... and as the disk cache fills, the HSM system migrates these files to the tape robot. We picked 1G because it seems like a safe and manageable file size.
To restore, you just do this:
cat dump.?? | rsh netapp restore -r -f -
Admittedly, it's clunky to restore individual files, but we use snapshots for that. These dumps are primarily for disaster recovery.
We do full dumps every month and level 3 dumps every week and level 5 dumps every day. To recover space on the tape robot, we simply rm old dumps from the filesystem. We have a nightly cron script that runs on the ADSM server that handles everything.
Steve Losen scl@virginia.edu phone: 804-924-0640
University of Virginia ITC Unix Support