RE: 10g RAC B&R Strategies

From: <krish.hariharan_at_quasardb.com>
Date: Sun, 9 Mar 2008 20:43:07 -0600
Message-ID: <001e01c88258$79e91330$6501a8c0@BHAIRAVIPC01>


Jeff,  

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.

Regards,

-Krish

Krish Hariharan

President/Executive Architect, Quasar Database Technologies, LLC

http://www.linkedin.com/in/quasardb


From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] 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?

Thanks,
Jeff

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Received on Sun Mar 09 2008 - 21:43:07 CDT

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