Large log backups

I noticed that my log backups are very very large after doing a full backup of my databases and was confused why that was.

I created 2 maintenance plans
- one for full backups and DB maintenance that runs nightly
- one for log backups that run at 4hr intervals

For whatever reason, the first transaction log backup that is performed after the full backup of the database is as large if not larger than my full backup, while subsequant log backups are more reasonable in size. Until the next full backup is performed, that is, then the next log backup is HUGE again...

Example:

05/04/2006 01:16 AM 35,801,484,800 TPRO_backup_200605032323.bak
05/04/2006 10:12 AM 31,236,731,392 TPRO_backup_200605040800.trn
05/04/2006 11:00 AM 159,274,496 TPRO_backup_200605041100.trn

No work is done in the database until after 8am, so nothing is going on in the database between the full backup (starts sometime after 10pm ) and the first transaction log backup (starts at 8AM), yet the first transaction log is nearly as large as the full backup that was done. Why?!? Sometimes the first log backup is even larger than the full backup.

If anyone can explain why this is the case and how I can fix it so that my log backups are more realistic, I would greatly appreciate it!

Thanks

Brandon

You mention DB maintenance that is run nightly but don't specify what that maintenance might be. If you're rebuilding indexes on all the tables it's quite conceivable your transaction logs are as large as the full backup file.|||

The order of tasks in the nightly maintenance job is as follows:

Check DB Integrity