Snapshot Consistency
Stagger snapshot schedules to ensure application synchronization, I/O quiescing, database verification, and so on. Consider the following points for different application types.
| Microsoft application snapshots | For some Microsoft applications, such
as Microsoft Exchange®, snapshots require that the application writes
are flushed to the database and traffic is stopped while the snapshot is
taken. This ensures that there is never partial data stored in the
snapshot. The OS performs this step automatically when Microsoft VSS synchronization is enabled. |
| VMware snapshots | If your data center uses VMware
vCenter, ensure that traffic is stopped while the snapshot is taken so
that the snapshot is complete and can be cloned directly to a new
virtual machine. The OS performs this step automatically when VMware vCenter synchronization is enabled. |
| Application-consistent snapshots with VMFS | The VMware snapshot captures the state and data of a virtual machine at a particular point in time. When creating a snapshot, VMware provides the "quiesce" option which flushes dirty buffers from the guest OS in-memory cache to disk, and offers application consistency through VSS requestor in VMware Tools. The Protection Manager takes advantage of the VMware quiesced snapshot option and combines it to achieve consistent and usable volume snapshots and replicas. |