Comments on: Recovery model and transaction logs

By: Deepali

Deepali — Thu, 07 Jan 2010 12:32:50 +0000

And Wishing You and the team a Very Happy New Year..

By: Deepali

Deepali — Thu, 07 Jan 2010 12:24:39 +0000

Thanks for Your reply Gail..
I created two jobs. One for Full Backup everyday and another for Tlog Backup every 2 hours.
Gail, can you please help me understand the concept of TLog Backups.

Like, if we have a verified full backup that can be restored, we are sure that data can be recovered.
Then we are also doing TLog backups.
But if we take a Full Backup, that has all the transactions upto that time, does that mean we can delete .trn files that were created earlier than that full backup.

By: Gail

Gail — Tue, 29 Dec 2009 17:24:07 +0000

Sounds reasonable.

If the log’s getting to 7GB, it may be worth reducing the interval between the log backups, should keep it smaller.

By: Deepali

Deepali — Tue, 29 Dec 2009 11:46:06 +0000

Thank You Gail.. Your advice is much help..!!
My DB size is 400 MB and mirroring has been setup and log file has grown to 7 GB.
That means if I create two DB Maint jobs, one for full backup everyday since DB size is not very large and another for log backup every 2 hours and retain each Full backup for last 5 times and Transaction log backup for last 20 times.. would that be enough for a point in time restore.

By: Gail

Gail — Mon, 28 Dec 2009 17:33:56 +0000

I’d retain for 2 full backups, just incase you go to restore the latest full and it’s corrupt. That way you can always use the older full and all the log backups since then.

It basically boils down to database recovery. The longer the backups are retained, the further back you can restore if needed for deleted data or due to newer backups being damaged.

By: Deepali

Deepali — Mon, 28 Dec 2009 16:24:54 +0000

For how long should the transaction log backups be saved on the disk so that disk space can also be saved ie. after a full backup and subsequent Transaction log backups and then a full backup, does the TLog backup become irrelevant because a Full backup has occurred now.

By: Gail

Gail — Mon, 06 Oct 2008 07:22:16 +0000

What I’m saying is to not do the truncation without the backup, that is, don’t run
BACKUP LOG WITH TRUNCATE_ONLY

That discards log entries without backing them up, hence breaking the log chain.

By: Marc

Marc — Sun, 05 Oct 2008 21:28:35 +0000

Hello…

From what I have read here, it appears that doing a Log backup automatically truncates the log. As long as you have the members of the “chain” (that is, the proper log backups). point in time restores are possible. I don’t understand why you state not to do the log truncation.