Apr 20 2015 17:29:27
Copyright (c) Microsoft Corporation
Enterprise Edition (64-bit) on Windows NT 6.3 <X64> (Build 9600: ) (Hypervisor)
We recently implemented a High Availability Group. We have been doing file group backups of our main production database for about a year. We do a full backup once a week on Sunday, we do differentials every night except Sunday and we do regular transaction
log backups.
The odd thing is that once we moved the database to the AOAG, the size of the backup files exploded for no apparent reason. We first noticed this with the differential backups, but it's also the full backups.
For example, we have one file group that is just under 42 GB. Prior to the AOAG, the size of the full backup for this file group tended to be around 10 GB and the differentials ranged between 200 MB to 1 GB. After AOAG the backup sizes exploded so that the full backup files are 16 GB but the differentials really exploded to 14 GB!
A bunch of the differential backup files even for our smaller file groups are around that same 14 GB size which is several times the size of the data files in some cases. All total our full backups went from taking about 425 GB now they are over 800 GB. Our differentials went from taking about 9 GB the day after the fulls to taking over 700 GB!
This is a huge problem for us. I've double checked and we are still using compression. Interestingly the transaction log backups are about the same size as before.
Any ideas on what's going on?