RMAN Read Only Tablespace

[lesstjm]

I have a 10.2.0.3 database on Solaris. I have an RMAN script that does a Hot Backup every day. It takes 9 hrs.

I was thinking about putting about 50% of the tablespaces in READ ONLY mode. The data never changes. It is part of a partitioned historical table.

After I put them in read only I take a hot backup and then the next time I add the skip readonly clause in my rman script. That is what I read.

My question is about retention. I have redundancy = 2. I am assuming it will never delete the read only tablespace backupset. Is that correct? Does anyone else use this read only skip feature?

[hrishy]

Hi

Not answering your question directly but still here are my thoughts which might be helpful.

In my opinion

I was thinking about putting about 50% of the tablespaces in READ ONLY mode.

This would be a very difficult task to do.

Have you looked at Block Change Tracking in 10g and doing incremental backups ?

Also look at the documentation
http://download-uk.oracle.com/docs/c...cmconc1008.htm

for the answer to your question
regards
Hrishy

[jhmartin]

Why would that be difficult? If the data is truly read-only and the table partitions do not change, and that is true of the entire tablespace, then it should work.

Granted, BCT and incremental backups are a very useful tool to reducing backup size and times.

[BV1963]

I am not 100% sure, but I think if you configure your retention policy to the redundancy 1(?) your will always have a backup of the read only tablespaces available.

[hrishy]

If the data is truly read-only and the table partitions do not change, and that is true of the entire tablespace, then it should work.

Most of the databases that i have come across its very difficult to isolate true read only tablespaces.

regards
Hrishy

[hrishy]

I am not 100% sure, but I think if you configure your retention policy to the redundancy 1(?) your will always have a backup of the read only tablespaces available.

yes you are right if the verbatim from docs is to be beleived

from the docs

Assume that you configure a retention policy for redundancy. 
In this case, RMAN only skips backups of offline 
or read-only datafiles to SBT 
when there are r + 1 backups of the files, 
where r is set in 
CONFIGURE RETENTION POLICY TO REDUNDANCY r.

[ebrian]

The important aspect is to set OPTIMIZATION ON.