Re: cron backups on RAC

> To list:: I'm configuring rman backups for our first RAC deployment, hopefully to be live in September.
> In the past, with single-instance Oracle, I have used cron to schedule daily backups from the database server.
> We have always licensed Tivoli for Oracle from IBM, this gives rman the interface to our Tivoli tape library.
> Now that we have a 3-node cluster, I'm trying to decide how to schedule backups; one of the nodes will be the preferred server,
> others will run the rman job only if the others are not available. I have seen reference to using dbms_scheduler,
> but this would not work if we wanted to run an offline backup. I would appreciate any ideas.

I used to be in the exact same situation as you when we deployed our first RAC. I've solved the issue by building a seperate machine which I configured as our RMAN server. That machine ran a single Oracle instance used exclusively for RMAN. (I checked with my Oracle rep and that machine didn't need licenses because it's used only for RMAN :)

The RMAN server's crontab is used to schedule all other Oracle instance backups. By using 11.2 RAC SCAN FQDN in the tnsnames.ora files, I could always backup our RAC clusters even if a node on those clusters was down. I created RMAN stored scripts to backup 9iR2, 10gR2 and 11gR2 databases. Those scripts created incrementally updated disk based RMAN backupsets for all the clients. I also used RMAN to backup the RMAN catalog to disk based backupsets. The client backupsets were dumped on an NFSv3 share from the RMAN server (so one can imagine this setup requires quite a lot of disk space, but disk is cheap, right?! ;o) I then used NetBackup to backup the entire RMAN server (along with all the client's backupsets) to tape and then sent those encrypted tapes off-site. It worked great!

But you have to keep an eye for the Oracle versions in that setup. As the RMAN server can't be running a higher version than the client. Well, no, it can, but you can't use an RMAN binary that's of a higher version then the client you want to backup. For instance, I could backup our 11gR2 RAC machines by using the RMAN server's 11gR2 rman binary. But I couldn't do this for the 9iR2 and 10gR2 instances. For those, I had to use their own lower versioned rman binaries. Using the older binaries, I could still use the 11gR2 RMAN catalog running on the RMAN server. Which meant that the 9iR2 and 10gR2 server's crontabs were still used to initiate the backups : not the RMAN 11gR2 server's crontab! Fortunately both of our RAC clusters were running 11gR2 so I was ok.

The « Oracle Database Backup and Recovery User's Guide 11g Release 2 » [*] and the following Metalink documents helped me build this setup.

Doc ID 1117597.1 - NFS options for 11.2.0.2 RMAN disk backups on Linux 64-bit.

Doc ID 360416.1 - Oracle10g / 11g - Getting Started with Recovery Manager (RMAN)
Doc ID 351455.1 - Oracle Suggested Strategy & Backup Retention
Doc ID 303861.1 - Incrementally Updated Backup In 10G

Let me know if you'd like more info.

> Thanks!

HTH, DA+

[*] http://download.oracle.com/docs/cd/E11882_01/backup.112/e10642/toc.htm

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