 Incremental Backups [message #455193] |
Mon, 10 May 2010 10:57  |
daddybigboy
Messages: 10
Registered: March 2010
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Junior Member |
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Incremental Backup Strategy:
Scenario:
Database is in archivelog mode
Block change tracking on
1. 1st Sunday of each month Level 0 incremental backup (full)
2. Monday - Saturday - differential incremental backup (level 1)
3. Sunday ( 2nd thru 4th Sunday) a cumulative incremental backup taken.
On the second Sunday of the month does the cumulative incremental backup take updated data blocks from the 1st Sunday when the increment level (0) backup was taken or does it take updated data blocks from the last incremental backup level (1) from Saturday night?
I understand the concept of doing cumulative incremental backups and differential backups separately but I am not sure about what happens when we mix them in a backup strategy.
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| Re: Incremental Backups [message #455201 is a reply to message #455193] |
Mon, 10 May 2010 11:09  |
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Michel Cadot
Messages: 68729
Registered: March 2007
Location: Saint-Maur, France, https...
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Senior Member
Account Moderator |
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Are you sure you need a comple backup strategy?
What is the goal you are trying to achieve?
What is the database size? The backup level 0 size? The incrfemental size (both differential and incremental)?
What is the amount of archived logs each day?
What are your restore requirements?
Regards
Michel
[Updated on: Mon, 10 May 2010 11:09] Report message to a moderator |
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| Re: Incremental Backups [message #455206 is a reply to message #455201] |
Mon, 10 May 2010 11:54 |
daddybigboy
Messages: 10
Registered: March 2010
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Junior Member |
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Hi Michel,
I have more than 90 databases. They range in size from approximately 50Gb to 50Tb. I am primarily interested in reducing the amount of time to backup.
I am simply looking for an answer to the question of whether the cumulative incremental backs up changes from the last incremental level 1 or does it go back to level 0 in a mixed backup strategy.
Please let me know if you have the answer on this. I know that the cumulative will normally go back to the last incremental 0 when only running cumulatives but I am not sure what happens when a differential level 1 is added to the mix.
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| Re: Incremental Backups [message #455209 is a reply to message #455206] |
Mon, 10 May 2010 12:11 |
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Michel Cadot
Messages: 68729
Registered: March 2007
Location: Saint-Maur, France, https...
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Senior Member
Account Moderator |
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It does not change the result of the incremental cumutalive backup whether there were previous cumulative or differential incremental backups (just the work rman has to do change).
If your concern is just backup time, you should only make differential backup.
Regards
Michel
[Updated on: Mon, 10 May 2010 12:11] Report message to a moderator |
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| Re: Incremental Backups [message #455216 is a reply to message #455209] |
Mon, 10 May 2010 12:31 |
daddybigboy
Messages: 10
Registered: March 2010
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Junior Member |
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Thanks for your response. To clarify, does that mean the cumulative incremental will always go back to the prior incremental 0 regardless of whether an incremental level 1 was taken in the interim? I think you are saying yes from your response but I am not sure.
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| Re: Incremental Backups [message #455224 is a reply to message #455193] |
Mon, 10 May 2010 12:51 |
daddybigboy
Messages: 10
Registered: March 2010
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Junior Member |
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Thanks for your help. I will have to come up with a set of criteria to determine how backups are to be performed in my environments. Incremental backups should always help to improve backup and recovery performance. As you have mentioned there are many factors to consider when trying to optimize for recovery. My next task will be to try and find some general rules of thumb or best practices to come with some standards for backing up my databases since one way doesn't fit every situation.
If you have any information on best practices, standards or white papers please let me know. Thanks again.
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