Message: "The VSS Snapshot was deleted by the system"

Summary:

CSSB uses the Windows Volume Shadowcopy Service (VSS) to take snapshots of data for backup. Snapshots are used to take backups of files that are open, in-use, or locked by the system.

Windows may delete a snapshot mid-backup for many reasons. If the snapshot is deleted, the message "The VSS Snapshot was deleted by the system." will be displayed.

CSSB will attempt to continue the backup by copying the files manually for File System backups, even if the snapshot is deleted. This only applies to Backup to Disk or Backup to Disk and Cloud operations.

Files that are locked, in-use, or open cannot be backed up without a snapshot. If one or more files fail to back up, the backup operation will complete and be marked with a warning status. If too many files fail to be backed up, the entire backup will fail. Please see Backup failed for too many files for more information.

For all other backup types and for all Backup to Cloud operations, the backup will fail completely if the snapshot is deleted by the system.

This article applies to:

Carbonite Plans	Products	Platforms
Power and Ultimate (Not sure?)	Carbonite Safe Server Backup (Not sure?)	Windows

Solution:

There are three primary reasons why a snapshot can be deleted, with three separate resolutions.

1. There is not enough space on disk

Snapshots take up space on the disk. If the disk is full, Windows will automatically delete snapshots to free space on the disk. Lack of free space is the most common reason for snapshot deletion.

Large backups may require more space on the disk for the snapshots. Ten percent (10%) free space is the minimum required; twenty percent (20%) free space is recommended. All disks must have at least 10% free space to ensure proper snapshot functionality.

2. There is not enough shadowstorage space allocated for snapshots

The space allocated for snapshots is known as shadowstorage. Shadowstorage space can be shown from an elevated ("Run as Administrator") Command Prompt. Run the following command within Command Prompt to list shadowstorage:

vssadmin list shadowstorage

The current shadowstorage for each volume will be listed. The Maximum Shadow Copy Storage space should be at least 10% of the volume, though twenty percent (20%) is recommended.

If the maximum shadow copy storage space is less than 20%, resize it using the following command (Replace X with the drive letter of your choice. Remember, 20% is the recommended value, but some systems can use as little as 10%):

vssadmin resize shadowstorage /for=X: /on=X: /maxsize=20%

If a volume has no shadowstorage listed at all, the shadowstorage must be created using the following command (Replace X with the drive of your choice):

vssadmin add shadowstorage /for=X: /on=X: /maxsize=20%

An explanation of all vssadmin commands can be found at the Microsoft article here: http://technet.microsoft.com/en-us/library/cc754968.aspx

3. One or more disks is failing

A failing disk can compromise VSS Snapshot functionality. Inspect all disks closely for corruption or other failures, verify whether there is enough disk space, and ensure that the shadowstorage is set correctly.

Please refer to this Microsoft article for more information on general VSS event IDs.