About VSS-based snapshot configuration

In NetBackup 7.0, the Enterprise Vault agent provides support for VSS copy-on-write snapshots and , however, the user is not allowed to configure it. In the Enterprise Vault policy type, the Snapshot check box is disabled because Snapshots have been automated to run under certain conditions.

The Enterprise Vault agent uses the snapshot mechanism in following scenarios:

An Enterprise Vault SQL database backup using a FULL schedule.
An Enterprise Vault File System data backup for a non-UNC (Universal Naming Convention) location.

Table: Conditions of when snapshot is used illustrates when snapshot is used.

Table: Conditions of when snapshot is used

Data type	Schedule type	Is a snapshot used?
Enterprise Vault SQL database	FULL	Yes
Enterprise Vault SQL database	Incremental	No
Enterprise Vault File System data is exposed as a UNC path (For example: \\server\share\data_path)	Any	No
Enterprise Vault File System data is exposed as a non-UNC path	Any	Yes

The following list contains additional the notes that relate to a VSS-based snapshot configuration:

The Enterprise Vault agent internally uses the VSS-based snapshot. Therefore, every drive that has the Enterprise Vault data must have an ample amount of free space for a VSS snapshot to be taken. A snapshot can fail if the amount of free space on the selected drive is insufficient.

See About the VSS_E_INSUFFICIENT_STORAGE snapshot error.
With NetBackup 7.0, the Enterprise Vault agent attempts to take as many snapshots per snapshot job as possible. The maximum number of snapshots that can occur during a single snapshot job is 64. That is also the default value. You have the ability to lower this value by adjusting the maximum number of snapshots that can occur during a single snapshot job. The registry DWORD value, MaxSnapshotPerJob controls the maximum number of snapshots. This registry value is located under the registry key, Software\VERITAS\NetBackup\CurrentVersion\Agents\EnterpriseVault\. The default for the MaxSnapshotPerJob value is 64 snapshots per snapshot job.