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yossim avatar image
yossim asked

Differential and full backup lsn not match

Hi, I have a maintenance plan that do a full backup one a week and diff backup every day. I noticed that the lsn is not match between the last differential and the last full. I don't understand how the last diff backups not match the last full backup? For some reason it match the one before the last full backup. The print screen that I attached come from query msdb.backupset and msdb.backupmediafamily Thanks ![alt text][1] [1]: /storage/temp/1727-backuphistory.png
backupdifferential-backuplsn missing
backuphistory.png (54.5 KiB)
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DenisT answered
This is a normal behavior! There is nothing wrong with the picture. Before a FULL backup is taken, SQL issues a checkpoint which becomes the first LSN and since it's a first LSN each DIFF backup has to include it. If you look at the picture, each FULL backup concludes the chain. You can run the came query but add checkpoint_lsn and first_lsn columns to it. You'll see what I am taking about.
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yossim avatar image yossim commented ·
Thanks for your answer. I added [checkpoint_lsn] column and now all is clear. :)
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