Hello all,
I'm currently on a mission to reduce our backup storage, thanks to running low in our object store.
One of our VBR jobs backs up a couple MSSQL servers in an Availability Group. It's already not using per-VM backup chains in the hope it will save a little extra space by deduping within the backup files (although I hear this is going away). A full backup is 14.7TB (so ~7.35TB/server) and incremental is 1-2.8TB (not sure if it's both servers or the active AG node creating the large space). What's extra special is the SQL log backups (.vlb files), which are only 5GB/day max.
I've read through a ton of posts here about CBT and how it can create inflated numbers. I already checked AV, defrag, and OS dedup. No local SQL backups. So I'm left to think that SQL server is doing something crazy that changes a ton of blocks, but doesn't cause much to actually go to the SQL log files. The SQL server supports a single app, and I already talked to the vendor about it. They don't know what's up either. If anyone has a clue what to look for that could cause this on the SQL side, I'd appreciate it, but that's not why I'm posting.
Considering the large difference between the SQL log backup files and the VM incremental backup, would it make sense to try a Veeam Agent instead? My hope is the Agent's method of CBT using the NTFS MFT will cause smaller backups than VMware's CBT. Thoughts?
I'm currently on a mission to reduce our backup storage, thanks to running low in our object store.
One of our VBR jobs backs up a couple MSSQL servers in an Availability Group. It's already not using per-VM backup chains in the hope it will save a little extra space by deduping within the backup files (although I hear this is going away). A full backup is 14.7TB (so ~7.35TB/server) and incremental is 1-2.8TB (not sure if it's both servers or the active AG node creating the large space). What's extra special is the SQL log backups (.vlb files), which are only 5GB/day max.
I've read through a ton of posts here about CBT and how it can create inflated numbers. I already checked AV, defrag, and OS dedup. No local SQL backups. So I'm left to think that SQL server is doing something crazy that changes a ton of blocks, but doesn't cause much to actually go to the SQL log files. The SQL server supports a single app, and I already talked to the vendor about it. They don't know what's up either. If anyone has a clue what to look for that could cause this on the SQL side, I'd appreciate it, but that's not why I'm posting.
Considering the large difference between the SQL log backup files and the VM incremental backup, would it make sense to try a Veeam Agent instead? My hope is the Agent's method of CBT using the NTFS MFT will cause smaller backups than VMware's CBT. Thoughts?
Statistics: Posted by BertM — Apr 16, 2025 6:07 pm
