This article will explain you the error "The Device is Not Ready" during a backup of MS SQL.
When we are backing up backup MS SQL, we create a snapshot with the help of the VSS of MS SQL databases.
The following actions can lead to an error causing loss of a snapshot:
- reboot of the server during a backup of MS SQL;
- restart of the Backup Service Controller during a backup of MS SQL;
- restart of the MS SQL writer or the VSS during the backup of MS SQL.
Most likely, this is a temporary issue and next backup will be successful.
NOTE: There is also a chance that the system deleted the snapshot by itself. You should check event logs in the time frame ±10 minutes of the fail.
In case VolSnap deletes the shapshot, you should tune your system to prevent it.