RE: 10g RAC B&R Strategies

From: Randy Johnson <>
Date: Tue, 18 Mar 2008 12:53:32 -0500
Message-ID: <001e01c88920$fc8766b0$8119fea9@scraunch>

[ So, is anyone actually doing this? That is, backing up the FRA to disk with the 'backup recovery area' command as per this Metalink note? ]  

I had a client who's tape backup software didn't play well with RMAN; that is it performed poorly and failed frequently. They were working on a replacement which took several months. We needed an interrim solution so we could continue to move forward with RMAN rollout. Here's how we did it.  

  1. Use RMAN to backup the databases to FRA.
  2. Using RMAN's oracle.disksbt device, backup the FRA to an NFS file system (a NetApp Filer). This file system was mounted by all our database servers and thus provided a nice centralized location for these "Tape backups".
  3. Backup the NFS filesystem to the tape library.

It was a good interrim solution but I wouldn't want to live there long. One obvious problem was coming up with a strategy for restoring backups from the tape library to the NFS volume and managing that space gracefully.  

My ideal tape backup solution would be to backup the FRA to a vitual tape library (VTL). This has all the the advantages of backing up directly to tape without having to manage/share a limited number of physical tape devices across all your databases. They perform very well and provide an integrated tape backup solution for RMAN. In this configuration your VTL's will be migrated to real tape and shipped off site periodically.  

    -Randy Johnson

From: [] On Behalf Of Sent: Sunday, March 09, 2008 9:43 PM
To:; 'oracle-l'
Subject: RE: 10g RAC B&R Strategies


I have seen several variants of "slow tape infrastructure". The bottom line is that you should be able to satisfy the throughput requirements of your backup. Having dealt with close to 80TB of backup using RMAN/NetBackup, I would examine the assertion that you are able to scrape your backups to tape
(after a write to disk) but not able do that do that directly to tape; a
different story if you are not licensed for the VERITAS DBE (rman libobk) then you are left to the task of scraping file systems.  

Since you have asserted that upgrading the tape subsystem is not feasible you can try a two pronged approach.  

  1. Backup to /backup: I would avoid the FRA unless you have other motivations. Implement /backup and application VIP and a listener to go with it which RMAN can attach to and thus RMAN connection would follow the VIP
  2. Determine the bottleneck on the slow tape infrastructure. Often times it is the network that surrounds it. In addition, depending on your version of Veritas NetBackup you have the Disk Storage Unit (DSU) option which can speed things up so that you are not bound by a circuit to tape.



Krish Hariharan

President/Executive Architect, Quasar Database Technologies, LLC

From: [] On Behalf Of Jeffery Thomas
Sent: Sunday, March 09, 2008 6:27 PM
To: oracle-l
Subject: 10g RAC B&R Strategies  

I have some serious doubts concerning our ability to devise a simple but robust B&R strategy
with 10g RAC given some architectural constraints.

We have a slow tape infrastructure where we cannot directly stream RMAN backups to tape.
Instead, with our current 9i VERITAS RAC systems, we have a shared file system (/backup) to which
we stream our RMAN backups, with nightly O/S backups coming along and copying the contents
of /backup to tape.  

We are nearly ready to start building some new 10g RAC systems on Solaris, and the plan was to
use a FRA. In addition, the plan was to use ASM only, no 3rd-party clustered file systems such as Sun
Clusterware or VERITAS. As a result we can have a /backup file system on only ONE node of the
cluster, due to the lack of a clustered file system other than ASM.

As stated in earlier threads in the Oracle-l archives as per RMAN backups to the FRA: "FRA is primarily
a backup to disk to tape strategy. Backup to the FRA then backup the FRA to tape."

Obviously, given our current configuation, we cannot do that.

As for backing up the FRA to disk, I found Metalink Note 420290.1, dated March 2007, "Backup Flash
Recovery Area to Disk Location":

"The 'backup recovery area' command only works with SBT (tape) channels. There is a planned fix to allow DISK
channels to be supported. The RMAN disksbt library, which emulates a SBT library (but writes backups to disk location), can be used as a supported workaround to backup the FRA to a disk location".

So, is anyone actually doing this? That is, backing up the FRA to disk with the 'backup recovery area' command as per this Metalink note?

As I see it, our options for backups, given: 1) No direct streams to tape, and 2) /backup file system on
one node are:

  1. Create the FRA, make RMAN backups to it, and try the SBT_LIBRARY option to backup the FRA to /backup.
  2. Create the FRA, make RMAN backups to it, and then backup the backupsets to the /backup file system, using something like this: 'backup backupset all format '/backup/...'
  3. Do not use the FRA to store RMAN backups. Only use the FRA for archived logs, and make our RMAN backups to /backup, similar to our 9i strategy. Not really a practical option.

Of course, for all 3 options, if the node where /backup is attached goes down, there might be a little problem.

Other than *fix the tape drives" (not going to happen), or "get a 3rd party clusterware in addition to ASM"
(possible), do we have other options?


Received on Tue Mar 18 2008 - 12:53:32 CDT

Original text of this message