About Protection Groups and Recovery Plans
A protection group is a collection of virtual machines and templates that use the same replicated datastore or
datastore group. A recovery plan specifies how the virtual machines in a protection group are recovered.
When the replicated devices that support a datastore group failover, that operation affects all of the virtual
machines and templates that use the datastores in the group. Because of this, SRM considers all of those virtual
machines and templates members of a single protection group. When you create a protection group, it initially
contains only those members that store all of their files on the selected datastore group. You can add members
to the protection group by creating them on that datastore, or by using Storage VMotion to move their storage
onto it. You can remove a member from a protection group by moving it to another datastore.
Recovery Plans and Replicated Datastores
A recovery plan is like an automated runbook. It controls every step of the recovery process, including the
order in which virtual machines are powered off or powered on, the network addresses that recovered virtual
machines use, and so on. Recovery plans are flexible and easy to customize.
A recovery plan applies to one or more protection groups. A protection group can be specified in more than
one recovery plan. For example, you could create one recovery plan to handle a planned migration of services
from the protected site to the recovery site, and another to handle an unplanned event such as a power failure
or natural disaster.
A protection group can be recovered by only one recovery plan at a time. If multiple recovery plans that specify
the same protection group are tested or run simultaneously, only one recovery plan will actually be able to
failover the protection group. Other running recovery plans that specify the same protection group report
errors for that protection group and the virtual machines it contains. Other protection groups covered by those
recovery plans are not affected by the errors.
Configuring and Maintaining the Protection of a Virtual Machine
Every virtual machine in a protection group must be configured in such a way that it can be added to vCenter
inventory at the recovery site. At a minimum, each machine needs to be assigned to a resource pool, folder,
and network that exist at the recovery site. An SRM administrator can specify defaults for these assignments.
These defaults, called inventory mappings, are applied when the protection group is created, and can be
reapplied as needed (for example, whenever you add a new virtual machine to the protected datastore). If you
do not specify inventory mappings, you must configure them individually for each member of the protection
group. Virtual machines that are on a protected datastore but improperly configured are not protected.
About Placeholder Virtual Machines and Inventory Mapping
For each virtual machine that you add to a protection group, SRM creates a placeholder at the recovery site.
These placeholders are added to, and can be managed as part of, the protected site's inventory.
When you add a virtual machine or template to a protection group, SRM reserves a place for it in the recovery
site's inventory by creating a subset of virtual machine files at the recovery site and then using that subset as
a placeholder to register the virtual machine with the recovery site vCenter. The presence of these placeholders
in recovery site inventory provides a visual indication to SRM administrators that the virtual machines are
protected, and to vCenter administrators that the virtual machines can be powered on and start consuming
local resources when SRM tests or runs a recovery plan.
No member of a protection group is protected until its placeholder has been created. Placeholders are not
created until valid inventory mappings have been established by either applying the site’s inventory mappings
to all members of a protection group or configuring mappings for individual members. If inventory mappings
have been established for a site, you cannot override them by configuring the protection of individual virtual
Site Recovery Manager Administration Guide
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