5.5

Table Of Contents
The replication scheduler tries to satisfy these constraints by overlapping replications to optimize
bandwidth use and might start replications for some virtual machines earlier than expected.
To determine the replication transfer time, the replication scheduler uses the duration of the last few
instances to estimate the next one.
Replicating a Virtual Machine and Enabling Multiple Point in Time
Instances
You can recover virtual machines at specific points in time (PIT) such as the last known consistent state.
NOTE You cannot use the SRM interface to configure replication that uses point in time (PIT) snapshots. To
enable PIT snapshots, configure replication of a virtual machine by using the vSphere Web Client. See
Configure Replication for a Single Virtual Machine in vSphere Replication Administration.
When you configure replication of a virtual machine, you can enable multiple point in time (PIT) instances
in the recovery settings in the Configure Replication wizard. vSphere Replication retains instances of the
virtual machine on the target site based on the number of retention policy that you specify.
vSphere Replication supports maximum of 24 instances. After you recover a virtual machine, you can revert
it to a specific snapshot.
During replication, vSphere Replication replicates all aspects of the virtual machine to the target site,
including any potential viruses and corrupted applications. If a virtual machine suffers from a virus or
corruption and you have configured vSphere Replication to keep PIT snapshots, you can recover the virtual
machine and then revert it to a snapshot of the virtual machine in its uncorrupted state.
You can also use the PIT instances to recover the last known good state of a database.
NOTE vSphere Replication does not replicate virtual machine snapshots.
Figure 21. Recovering a Virtual Machine at Points in Time (PIT)
vSphere Web Client
VR Appliance
t1
VM
VM VM VM
t3t2
vSphere Web Client
VR Appliance
VM
Replication
Source Site
Target Site
t0
SRM only recovers the most recent PIT snapshot during a recovery. To recover older snapshots, you must
enable the vrReplication > preserveMpitImagesAsSnapshots option in Advanced Settings in the SRM
interface. See “Change vSphere Replication Settings,” on page 88.
To recover a virtual machine from an older PIT snapshot, you must manually revert the virtual machine to
that snapshot after the recovery. See “Recover a Point-in-Time Snapshot of a Virtual Machine,” on page 46.
Configure Replication for a Single Virtual Machine
vSphere Replication can protect individual virtual machines and their virtual disks by replicating them to
another location.
When you configure replication, you set a recovery point objective (RPO) to determine the period of time
between replications. For example, an RPO of 1 hour seeks to ensure that a virtual machine loses no more
than 1 hour of data during the recovery. For smaller RPOs, less data is lost in a recovery, but more network
bandwidth is consumed keeping the replica up to date.
Site Recovery Manager Administration
22 VMware, Inc.