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Table Of Contents
How SRM Interacts with vSphere High Availability
You can use SRM to protect virtual machines on which vSphere High Availability (HA) is enabled.
HA protects virtual machines from ESXi host failures by restarting virtual machines from hosts that fail on
new hosts within the same site. SRM protects virtual machines against full site failures by restarting the
virtual machines at the recovery site. The key difference between HA and SRM is that HA operates on
individual virtual machines and restarts the virtual machines automatically. SRM operates at the recovery
plan level and requires a user to initiate a recovery manually.
To transfer the HA settings for a virtual machine onto the recovery site, you must set the HA settings on the
placeholder virtual machine before performing recovery, at any time after you have configured the
protection of the virtual machine.
You can replicate HA virtual machines by using array-based replication or vSphere Replication. If HA
restarts a protected virtual on another host on the protected site, vSphere Replication will perform a full
sync after the virtual machine restarts.
SRM does not require HA as a prerequisite for protecting virtual machines. Similarly, HA does not require
SRM.
Protecting Microsoft Cluster Server and Fault Tolerant Virtual
Machines
You can use SRM to protect Microsoft Cluster Server (MSCS) and fault tolerant virtual machines, with
certain limitations.
To use SRM to protect MSCS and fault tolerant virtual machines, you might need to change your
environment.
General Limitations to Protecting MSCS and Fault Tolerant Virtual Machines
Protecting MSCS and fault tolerant virtual machines is subject to the following limitations.
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You can use array-based replication only to protect MSCS virtual machines. Protecting MSCS virtual
machines with vSphere Replication is not supported.
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Reprotect of MSCS or fault tolerant virtual machines requires VMware High Availability (HA) and
VMware Distributed Resource Scheduler (DRS). When you move MSCS or fault tolerant virtual
machines across their primary and secondary sites during reprotect, you must enable HA and DRS, and
set the affinity and antiaffinity rules as appropriate. See “DRS Requirements for Protection of MSCS
Virtual Machines,” on page 42.
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vSphere does not support vSphere vMotion for MSCS virtual machines.
ESXi Host Requirements for Protection of MSCS Virtual Machines
To protect MSCS or fault tolerant virtual machines, the ESXi host machines on which the virtual machines
run must meet certain criteria.
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You must run a fault tolerant virtual machine and its shadow on two separate ESXi Server instances.
Chapter 4 Creating, Testing, and Running Recovery Plans
VMware, Inc. 41