Performance Impact of Empty file by migrating the data to other files in the same filegroup

Question

We have a database currently sitting on 15000 RPM drives that is simply a logging database and we want to move it to 10000 RPM drives. While we can easily detach the database, move the files and reattach, that would cause a minor outage that we're trying to avoid.

So we're considering using DBCC ShrinkFile with EMPTYFILE. We'll create a data and a transaction file on the 10000 RPM drive slightly larger than the existing files on the 15000 RPM drive and then execute the DBCC ShrinkFile with EMPTYFILE to migrate the data.

What kind of impact will that have?

Answer 1

Why not using log shipping. Create new database on 10.000 rpm disks. Setup log shipping from db on 15K RPM to DB on 10k RPM. When both DB's are insync stop log shipping and switch to the database on 15K RPM.

Answer 2

I've tried this and had mixed luck. I've had instances where the file couldn't be emptied because it was the primary file in the primary filegroup, but I've also had instances where it's worked completely fine.

It does hold huge locks in the database while it's working, though. If you're trying to do it on a live production system that's got end user queries running, forget it. They're going to have problems because it'll take a while.

Answer 3

Is this a system connected to a SAN, or is it direct attached storage? If its a SAN do a SAN side migration to the new raid group and the server won't ever know there was a change.