September 19, 2016 at 3:54 pm
Here's the scenario:
Need to test out new backup path.
So, in the jobs added step to backup in current and new path.
Full backup at 9 PM in two different backup paths.
T-log backup every 15 mins in two different paths.
Will this kind of criteria break the LSN chain and unable to restore T-log backup?
September 19, 2016 at 5:33 pm
Describe 'in two backup paths'.
Are you backing up to two locations at the same time using the MIRROR TO keyword of the BACKUP command? If that's what you mean, then your transaction log chain is safe using files from either location. You have two copies of everything: one in each location. Mirroring backups to multiple locations using MIRROR TO has saved my tail in the past.
If you are running two separate backups - one to the first location, followed by one to the second, then you are going to screw up your log chain.
When it's time to restore a database, you will need every transaction log backup after whichever full backup from which you are restoring, regardless of where you put that file. If you alternate the location of where you are backing up the transaction log, you're putting half of the files in one location, and half in the other. Every transaction log backup is unique; it contains the changes since the last log backup.
Because full backups do not break the log chain, you can scatter those around without issue beyond finding the right file when you need it.
Eddie Wuerch
MCM: SQL
September 20, 2016 at 3:15 pm
Thank you for the reply.
What I did was stopped the T-log backup,changed the path of full backup to new path, executed it and then changed and ran the T-log to new path once the full backup was complete.
Another question I have is:
Stopped T-log backup which points to old path at 9:55 PM.
Changed the full backup path to new and scheduled it to run on every Friday 10 PM.
Differential to new path everyday at 2 AM.
Changed T-log backup job to new path and scheduled to run every 15 minutes starting starting Friday at 10:15 PM.
Would this break the LSN chain? Should I run the T-log backup once full backup and differential backups are complete?
September 20, 2016 at 4:15 pm
That will not break the transaction log chain, because you still have every transaction log backup you've taken. The oldest of them reside in one location, the newest reside in another. The combination of both of these directories are you log chain. If you delete the files in the original location, then your chain is broken. I encourage you to consolidate those files somewhere.
Eddie Wuerch
MCM: SQL
September 20, 2016 at 4:19 pm
But, wouldn't the T-log on new path will be attached to new full backup on new path?
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