We are upgrading from SQL 2008 to SQL 2012, our environment has 6 TB of data (80 DBs) all mirrored to another server.
I saw it is recommended to run DBCC CheckDB after the upgrade. my problem is that it takes a very long time to run it, and it consumes a lot of CPU.
I will run a DBCC CheckDB NOINDEX every weekend (it takes 26-40 hours).
I'm using the rolling upgrade method. (meaning keeping the mirror active (suspended) while upgrading both servers).
I have a few questions on it:
1. If I run the DBCC on the first server, do I need to re-run it again when upgrading the replica a day after?
2. Which options can I use with the DBCC CheckDB to reduce the timing, while keeping the requirement of running DBCC CheckDB on the upgrade process:
- NoIndex
- Physical_only
- No Infomessage
3. What is the risk that I take if I continue working before doing DBCC CheckDB. Do I have to wait with the second replica not being upgrade until I get this task done on the first one (to allow fallback if needed)?
4. Is there a point on running the DBCC CheckDB even when running an in-place upgrade and NOT changing the compatibility level yet?
