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SQL Server Backup Schedule Overlap

Submitted by: @import:stackexchange-dba··
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sqloverlapserverschedulebackup

Problem

I have a SQL SERVER DB that i want to backup via automated schedule (using GUI maintenance plan) . I have 2 choices when configuring a schedule :

1) do not bother about log backup , full backup and diffrencial bakcup event time , as if all the 3 backups occur on same time , it makes no difference .

2) make sure that log backup, full backup and differential backup never occur in same time by configuring carefully the time of each backup.

Below is the image describing the 2 choices (Schedule1 for choice 1 and chedule2 for choice 2 )

Do you know which one is the best ?

Edit : Sechdule1 may face some errors when backups are overlaping . Here the backups are of type log and differential hapening same time at 5:30 as the backup whatever the type is will be appended to the existing backup file. So the file was in use by log backup and differential failed . Even if no data was lost.

Solution

First step: Understand how backups really work. The main things to understand:

  • Log backups after SQL Server 2000 can be taken concurrently during full and differential backups. The only thing to remember is during that timeframe the log will not be cleared until that full or differential backup completes.



  • Full and differential backups that collide will cause whichever backup started first to take precedence, the second backup will wait in line until prior backup is completed. So if you have a FULL backup running, and a DIFF backup starts, that DIFF backup will wait until the FULL is complete. I do believe it should be the same for the opposite as well.



Second Step: Whichever backup plan you choose ensure it meets the recovery requirements for the application AND/OR the business.

So while either schedule will work the schedule 2 will likely lessen the amount of IO activity that is caused when the backups overlap. It would based on the size of the database and how much activity SQL Server has to backup during the differential and log backups. Depending on how you setup schedule 1 you could end up with all three backups trying to occur at the same time frame.

Context

StackExchange Database Administrators Q#121779, answer score: 4

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