RMAN Parameter\Setting Question 1

[Michael42]

Hello,

On a Solaris 8 system I have an environment that does NOT use a catalog. I was trying to make sense of the relation of the Oracle parameter CONTROL_FILE_RECORD_KEEPTIME and the RMAN setting CONFIGURE RETENTION POLICY TO RECOVERY WINDOW of n DAYS.

I know that Oracle stores backup information in the control file in this environment. After reading the Oracle docs I guess I am still confused as to what these settings actually do and if they relate in any way.

Could someone please describe what what they do and possibly advice on usage?

Thanks,

Michael42

 

[eagertotry]

The 2 parameters actually are for different purposes. CONTROLFILE_RECORD_KEEPTIME is used to keep the control file size from becoming too big on account of storing too many records of archive log history (v$loghistory) or backup details (in case no catalog is used). Archive log history is stored regardless of RMAN being used or not. Based on this parameter, Oracle would reuse older records rather than extending the size of control file but only if the records are truely reusable. For example, if any of the data files need recovery, archive log history cannot be removed or reused.

Retention policy in RMAN governs not only the catalog info stored (in your case in the control file)
but also the actual backup copy of archive logs on disk or tape. RMAN is autoamtically able to delete the backup copies beyond the recovery window. As long as RMAN doesn't determine the catalog info to be removable, it will not be removed/reused from controlfile regardless of CONTROLFILE_RECORD_KEEPTIME.

I would recommend to pick a KEEPTIME of your choice, say, 30 days and you should be fine. Choose a retention policy independently based on your backup needs.

 

[Michael42]

eagertotry,

Thanks for the very clear explanation.

-Michael42