Partition alignment is a setup trick for disk-intensive apps like Exchange and SQL Server that can have a 30% or more performance impact on  your server.  The setup information is in my SQL Server Setup Checklist, and Jimmy May has more details on the mechanics of partition alignment.

If you run SQL Server in VMware, this still applies to you.  Today, Duncan Epping of Yellow Bricks (a VMware-focused blog) brings news of a new way to test whether your virtual machines have been set up correctly with partition alignment.  VMware admins can run a script on their VMware host, which scans all of their guests and makes sure their partitions are aligned.

The bad news is that it can’t actually fix the partition alignment – the only way to do that right now is to delete the partition, which means a complete backup and restore with a lot of downtime.  The article hints that NetApp is building a utility that will fix partition alignment on VMware guests on the fly.

For more details, read Duncan’s blog entry about VM partition alignment.