Backups versus Snapshots
A backup contains all the rowstore data in-memory (of committed transactions) as well as the columnstore blobs.
A snapshot contains only the rowstore data in-memory (of committed transactions).
Backups are a safety measure for restoring the cluster in case some major cluster-wide issue occurs.
The BACKUP command is intended as a way to store a copy of your data that you can use to RESTORE from.
SNAPSHOT truncates the transaction log.ALTER TABLE
), or before you perform maintenance operations that require restarting the leaf nodes.
Another recommendation is to take a backup of the databases involved beforehand, then after any schema and data changes have been performed successfully, take snapshots as well to ensure that the next time you recover a cluster, it does not have to replay all the recent changes.
Snapshots run in a matter of minutes, unlike backups which can take several hours.
Restoring from a snapshot is not supported, it can be done only from a backup.
Last modified: July 30, 2024