probkup AI

[richieasir]

hi all,
can we use PROBKUP to backup AI files?if not,why?

thanks

 

[TomBascom]

No.

It would be pointless. If you have a backup you do not need the AI extents that are present at that time. AI files are used to roll forward against a previous backup.

To roll-forward you need all of the archived AI extents since a backup. There are very likely to be more archived extents than db ai extents because as they fill you copy them somewhere and rotate through the db AI extents. You might, for instance, define 8 AI extents for your db and switch extents every 15 minutes. When you switch extents you make a copy of the full extent and put that copy somewhere safe (preferably in another time-zone). In this case every 2 hours you will rotate through your AI extents. If you do a nightly backup and a horrible crash occurs just prior to Tuesday's backup you will need the Monday backup plus the 23 archived AI extents that were made during the day on Monday. AI extents from the Monday night backup are useless and irrelevant.