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pradnyag41 avatar image
pradnyag41 asked

How does transaction log backup job work without a full backup of database?

In our environment we have restored a DB with name TEST from existing DB XYZ backup file on that instance. The tlog backup job is running fine without full backup for TEST DB
transaction-logbackup-restore
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pradnyag41 avatar image pradnyag41 commented ·
The point is that Tlog backup job is running for TEST DB though there is no any full backup for this DB. Its also creating .trn files for TEST DB with full backup.
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ThomasRushton avatar image
ThomasRushton answered
It *should* ignore the Test DB until a full backup has been done. However... Are you getting any error messages from your TLog backup job?
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KenJ avatar image KenJ commented ·
It won't matter if the full backup came from another instance; it becomes the anchor for the log chain on whichever server you restore it. One full backup can be the source for hundreds or thousands of databases and they will all be able to take transaction log backups based on that single full backup.
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KenJ avatar image KenJ commented ·
A full backup *has* been done. They restored from it.
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pradnyag41 avatar image pradnyag41 commented ·
we dont have any full backup for TEST DB till date.
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KenJ avatar image KenJ commented ·
I'd be curious to learn how you restored database TEST without a full backup of database XYZ. That would be the full backup that is anchoring the log chain.
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pradnyag41 avatar image pradnyag41 commented ·
ok I got your point. But I have TEST2 DB which is restored on instance 1 from some other DB backup of other instance at on that time also tlog backup job is working fine.
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pradnyag41 avatar image pradnyag41 commented ·
How does it anchor a log chain if DB names are different?
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pradnyag41 avatar image pradnyag41 commented ·
How it resumes log chain of new DB with existing backup of another DB
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