Partial backups provide a means for eliminating read-only data from a backup. In some implementations, a portion of the data in a database may not change and is strictly used for inquiry. If this data is placed on a read-only filegroup, you can use partial backups to back up everything except the read-only data. This technique reduces the size of your backup and the time it takes to complete the backup. The read-only filegroups should still be backed up, but this needs to occur only after the read-only data is loaded.