Do you have quite large MDF files on your database? By large, I mean hundreds of gigabytes (or larger). Have you ever noticed that your SQL Server disk stall metrics for these data files are much higher than the storage latency metrics exhibited on the underlying operating system layer? It could be that your SQL Server data files are being hammered too hard and you don’t have enough data files to help the SQL Server storage engine distribute the load. We do this for tempdb, right? Why don’t we do this enough for our user databases as well? It’s easy for a brand-new database from day zero, but what about existing databases that have grown out of control with a single data file attached? Let me show you how to adjust this for existing databases without an outage!
Check it out. This is a part of database administration I’d never really thought much about, so it often ended up being a blind spot for me.