RE: incremental backups

From: Allen, Brandon <Brandon.Allen_at_OneNeck.com>
Date: Wed, 7 Mar 2007 15:00:15 -0700
Message-ID: <04DDF147ED3A0D42B48A48A18D574C45071FD73E@NT15.oneneck.corp>

No noticeable impact that I've seen, but I haven't really looked for one. I would think you'll want your change tracking file on a fast disk(s), just like redo logs, to prevent waits on the I/Os.  

Here's what the docs say about it:  

From
http://download-west.oracle.com/docs/cd/B19306_01/backup.102/b14192/bkup 004.htm#i1032148  

"Change tracking is disabled by default, because it does introduce some minimal performance overhead on your database during normal operations. However, the benefits of avoiding full datafile scans during backup are considerable, especially if only a small percentage of data blocks are changed between backups. If your backup strategy involves incremental backups, then you should enable change tracking."  

Here are my backup sizes and times through 3 channels to Netbackup for L0 (full) incremental:  

Database              BS_Key Start        End          Minutes Backup
Type   Status       #Files Database Size MB Written Size MB

-------------- ------------- ------------ ------------ -------

• ------------ ------ ---------------- --------------- BAANPRD 217142 01/20:13:59 02/02:26:02 372.05 Full Available 12 85752.00 84079.18 BAANPRD 217141 01/20:13:59 02/02:06:19 352.33 Full Available 13 85826.00 78825.81 BAANPRD 217143 01/20:13:59 02/02:47:42 393.72 Full Available 13 93845.25 89675.25

And then for L1 with change tracking file:  

Database              BS_Key Start        End          Minutes Backup
Type   Status       #Files Database Size MB Written Size MB

-------------- ------------- ------------ ------------ -------

• ------------ ------ ---------------- --------------- BAANPRD 220433 06/20:12:12 06/20:13:57 1.75 Incremental Available 13 85826.00 1018.24 BAANPRD 220432 06/20:12:12 06/20:13:50 1.63 Incremental Available 12 93952.00 890.14 BAANPRD 220434 06/20:12:11 06/20:13:59 1.80 Incremental Available 13 85773.25 1125.14

Regards,
Brandon  

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From: oracle-l-bounce_at_freelists.org
[mailto:oracle-l-bounce_at_freelists.org] On Behalf Of Manmohan Jalsingh

Any idea on performance impact on database by using block change tracking feature.

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http://www.freelists.org/webpage/oracle-l Received on Wed Mar 07 2007 - 16:00:15 CST