This wait type accumulates while requests SQL Server is waiting for a storage level (snapshot) backup to complete. These backups freeze all I/O on the volume to enable backups of large databases to be performed in seconds. Small accumulated values are acceptable. If an individual wait takes over 5 seconds investigation is required.
- Make sure snapshot backup drivers and software are up to date.
- Ensure snapshot backup drivers and software are configured correctly.
- Move non critical files and databases off the snapshot volume (the less I/O to freeze the better).
Consider using ApexSQL Monitor, a Windows and SQL Server monitoring tool able to track SQL Server wait types, including the individual query wait statistics