I have an Exchange 2010 server running on a SAN-backed platform. The platform does block-level backups based on a snapshot/incremental basis, that only capture changed data. I was surprised to see a regular period of time where the data changes were happening at a high, sustained rate. Due to the way this system works, that can lead to >1.2TB of stored data per month.

The regularity implied a scheduled task, but it is not a fixed interval. It is approximately every 26-32hrs. The disks were performing read operations of ~5MB/s and write operations of ~4.5MB/s, for a period of 3-4hrs. The total written data was ~55-60GB.

Reading on TechNet, I am wondering if the following is causing this: http://blogs.technet.com/b/exchange/archive/2011/12/14/database-maintenance-in-exchange-2010.aspx#checksumming

The somewhat restrictive thing is that the process only happens at most once every 24 hours. I was able to investigate while it was running, finding the following:

• the process is store.exe
• it is working on the mailbox database files
• while running, it is generating .log files (in the mailbox database folder) consistent with database changes
• the mailbox database is ~60GB in size, which fits with the total data changes on each iteration

I have currently switched to a fixed maintenance window, as a test. It's not clear whether this is the cause, as the symptoms fit, but are not conclusive.

Does anyone have any suggestions for additional troubleshooting?