RE: CommVault - dedup and software compression
Date: Fri, 21 Oct 2016 17:47:07 +0000
Message-ID: <1AFD62082EEAF0448EF1815139687F1369BFC41C_at_NC2PWEX504.us.ad.lfg.com>
Are you using RMAN compression or encryption on the datafiles as they come out of the database for backup? It is often recommended to turn these features off for dedup activity to perform it’s best.
For reference: http://kb.commvault.com/article/ORA0001
Chris..
From: oracle-l-bounce_at_freelists.org [mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Sandra Becker
Sent: Friday, October 21, 2016 11:16 AM
To: oracle-l
CommVault v11
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Chris Ruel * Oracle Database Administrator * Lincoln Financial Group
cruel_at_lfg.com<mailto:cruel_at_lfg.com> * Desk:317.759.2172 * Cell 317.523.8482
Subject: CommVault - dedup and software compression
Oracle Database versions 11g and 12c
We have been configuring clients and scheduling backups in CommVault for about 3 months now. While most backups work well and dedup as expected, we have concerns about two very large Exadata databases. The production database is 34T and the backup is taking 4-5 days. After pruning as much data as possible in the test database, it is down to 9T, with the latest backup taking just over 23 hours. Prior to pruning, backups were taking 3-4 days. It doesn't appear that the dedup feature is actually being used for either backup. I know that our CV admin opened a ticket with support, who in turn killed my production backup so they could test something. I was not happy since I was never consulted before they killed the backup. But I digress. Unfortunately, we have only a 1GB NIC to handle most of the backup traffic which means throttling our backups more severely than originally planned. We do have a request to replace the 1GB with a 10GB, but it doesn't look like that will happen any time soon. So, a couple of questions:
1. What would cause the dedup feature to not be used? I know for the test database we imported several hundred GB of data in the past week and obviously, that would not be deduped. The production database is a data warehouse, loading less than 100GB per day. Any other possible causes?
2. If we turn on software compression on the client, what effect/impact will that have, if any, on the deduplication?
I haven't been able to find the answers in the documenation yet. Any help would be greatly appreciated.
Sandy B.
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Received on Fri Oct 21 2016 - 19:47:07 CEST