Enterprise Vault services could be stopped automatically if any disk volume in the system is full. In addition, the Enterprise Vault services could stop if the client is also a media server and if a disk storage unit is full. In this situation, you would start the Enterprise Vault services and re-run the backup.
Quiescence can fail if the Enterprise Vault component (Vault store or Index location) or its parent component (such as, vault store group or site) is already quiesced. The backups fail with a status 2. You should clear the backup mode and attempt to run the backup again.
A backup can fail with a status 2 if the backup runs within a few minutes from when an Enterprise Vault directory database was restored. You should browse the Enterprise Vault configuration from Vault Administration Console and attempt to run the backup again.