Is it possible to test the incremental backups ... well, incrementally? If so: How? -and not using the words "duplicate" and "standby".
Setup
After the level 0 backup, we ship all backup files to a test rig (offline for all intents and purposes) and perform a full restore and recovery. What i want, is to move the incremental backup (< 50G) to the test rig and test only those bits. A recovery test could (in my head) complete in minutes, alternatively in a few hours if the readonly data could somehow be preserved. Otherwise it takes ~9 hours for a full restore+recovery.
The ultimate goal is to reduce the disaster recovery testing time by the ~70% taken by the readonly tablespace on the 12 hour incremental cycles - a full restore/recovery once a week is required by policy.
If my - as yet incomplete - solution is way off suggestions are most welcome (still not using "duplicate" or "standby" :o).
EDIT Oct 4 2011: So i figured out how to avoid restoring the readonly tablespace on every test, so that's 70% time saved. What remains is to figure out whether it's possible to restore only the latest incremental backup onto the test-rig.
To be clear: Sunday I end up with at fresh restore+recover of everything, including readonly. Every 12 hours I perform a new restore-test, which skips the readonly bits but performs a level 0 restore of the remaining 30%, then applies the incrementals - in effect rolling back to Sunday and then catching up to the latest incremental.
What I'd like is to do a full restore sunday, and every 12 hours "apply" only the latest incremental backup to this restore and avoid the rollback to Sunday.
I feel this needs to answered, if only partially, so here you go:
The recovery-part is still open, but avoiding the readonly-tablespace bit is solved using transferable tablespaces. Basically,
We did this for a 3TB tablespace, took all of 30 seconds. (and 10 hours to copy :oP)
A word of caution: marking as transferable and dropping a tablespace may not be the right thing to do, especially if you have dependencies between tablespaces.