RMAN Incrmental backup clarification

[hannah00]

I was reading RMAN book. FOr diffrential, it's all clear but I have question about incremental backup method:

If you have Sunday backup as level 0, this will backup the entire database. You do level 2 backup on Monday so whatever blocks changed from Sunday to Monday will be backup. you do another level 2 backup on tues so RMAN will backup blocks changed from Mon to Tues and from Sun to Mon as well.

Let's say, you do level 1 backup on Wed, the book said it will contain all the block changed from Monday, Tues and Wed. Thing I am not clear is that if level 2 will backup whatever the changed on Mon and Tues, why can't we do another level 2 backup on Wed instead of level 1??? Why do we need level 1 on Wed ????

thanks and have a great weekend.

[marist89]

you can do another level 2 on Wednesday, there's nothing stopping you. The point to a level 1 is to reduce the mean time to recovery (MTTR) if your database dies Friday. If you had a bunch of level 2's, you would have to apply Mon, Tue, Wed, Thur, Fri. If you had a level 1 on Wed, you would have to apply Wed, Thu, Fri.

Personally, I like Level 0 on the weekend and Level 1 cumulative on the other days. This way you are (almost) assured of applying only the latest level 1 during a restore.

[hannah00]

that made sense.

As usual, thanks so much for your help.

[hannah00]

I have another question regarding about RMAN.

Let's say, if you have a full backup on the weekend and incremental backup on the weekday, I am thinking about splitting these into two folder: one call D:\BACKUP\FULL and one for D:\BACKUP\INCREMENTAL.

The reason I am doign this so that the SYS admin can backup the FULL folder on the weekend and INCREMENTAL folder on the weekday so that it cut down the backup time and resources on the weekday.

1. is it how you guys set up in your shop???
2. any issues for recovery????

thanks again