Re: How are you backing up your V,VLDB????

> If RMAN is working in conjunction with Legato, would the two together have
> enough smarts to prevent the over-writing of a 3-month-old tape on which a
> 'kept forever' backupset is located?
>
> My suspiscion is not, but having never worked out how to get Legato working
> properly, I don't know for sure, and can't test it.

No, RMAN and Legato don't do *that* much talking together. Legato has it's tape retention policies which are defined on the Legato server. This way, Legato can automatically create room on tapes after a certain period of time. At our installation, we have this retention time set to 3 months. But we can configure this if we need to.

After three months is up, Legato makes the tape available for reuse. So when RMAN goes to backup again, it may well use this tape, overwriting its contents. Then, if you go to do recovery, and RMAN needs the file(s) that was on this tape, it is all lost. So RMAN and Legato don't work together in this aspect. But this is one of the reasons why I suspect Oracle Corp let you put retention policies in your RMAN recovery catalog. Now that I have these databases on 9i, I can set up my RMAN catalog with the Legato retention policy and I don't have to manually remove expired backup sets from the RMAN catalog like I had to in the Oracle 8i days.

Basically, the RMAN/Legato interface is just a fancy way of RMAN saying "here is a datafile. you take it." Then, Legato finds a spot for it on tape somewhere. Then, in recovery, RMAN tells Legato "I need datafile XXXXXX". Then Legato instructs the silo to mount the appropriate tape and gives the file back to RMAN. All of this is facilitated by purchasing the Legato Module for Oracle from Legato Corp, all for the low, low price of $6,000 per server (at least that was our cost).

Cheers,
Brian Received on Thu Jan 30 2003 - 13:43:10 CST