Moreover, because Snapshots require little time and little storage space, they can be taken several times per day, enabling more frequent full database backups. The storage overhead associated with a Snapshot is based on the number of blocks that are different between the Snapshot and the active file system. Only as blocks in the active file system are modified and written to new locations on disks will Snapshot begin to consume extra space. If multiple Snapshots exist for a file system, the only Snapshot that actually consumes disk space is the oldest Snapshot. The oldest Snapshot holds the changed data blocks until it is deleted, after which point the next oldest Snapshot holds the blocks.
Snapshots also provide key advantages in the restoration and recovery of databases.
This paper focuses on the use of Snapshots and SnapRestore for the backup and restore of SQL Server 2000 databases stored on a Network Appliance filer. While the use of this backup and restore method is both highly efficient and highly reliable, the use of SQL Server 2000's own backup and restore tools is also a viable choice when storing databases on a Network Appliance filer. Configuration for Database Recovery SnapRestore is a powerful tool that will restore an entire file system back to a previous state. You can configure the layout of your database to take advantage of this tool in several ways. Place the data files and log files from the SQL Server database onto a single volume on the filer.