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Table Of Contents
How Site Recovery Manager Interacts with DPM and DRS During
Recovery
Distributed Power Management (DPM) and Distributed Resource Scheduler (DRS) are not mandatory, but
Site Recovery Manager supports both services and enabling them provides certain benefits when you use
Site Recovery Manager.
DPM is a VMware feature that manages power consumption by ESX hosts. DRS is a VMware facility that
manages the assignment of virtual machines to ESX hosts.
Site Recovery Manager temporarily disables DPM for the clusters on the recovery site and ensures that all
hosts in the cluster are powered on when recovery or test recovery starts. This allows for sufficient host
capacity while recovering virtual machines. After the recovery or test is finished, Site Recovery Manager
restores the DPM settings on the cluster on the recovery site to their original values.
For planned migration and reprotect operations, Site Recovery Manager also disables DPM on the affected
clusters on the protected site and ensures that all of the hosts in the cluster are powered on. This allows
Site Recovery Manager to complete host level operations, for example unmounting datastores or cleaning
up storage after a reprotect operation. After the planned migration or reprotect operation has finished,
Site Recovery Manager restores the DPM settings on the cluster on the protected site to their original values.
The hosts in the cluster are left in the running state so that DPM can power them down as needed.
Site Recovery Manager registers virtual machines across the available ESX hosts in a round-robin order, to
distribute the potential load as evenly as possible. Site Recovery Manager always uses DRS placement to
balance the load intelligently across hosts before it powers on recovered virtual machines on the recovery
site, even if DRS is disabled on the cluster.
If DRS is enabled and in fully automatic mode, DRS might move other virtual machines to further balance
the load across the cluster while Site Recovery Manager is powering on the recovered virtual machines. DRS
continues to balance all virtual machines across the cluster after Site Recovery Manager has powered on the
recovered virtual machines.
How Site Recovery Manager Interacts with Storage DRS or Storage
vMotion
You can use Site Recovery Manager when protecting virtual machines on sites that are configured for
Storage DRS or Storage vMotion if you follow certain guidelines.
The behavior of Storage DRS or Storage vMotion depends on whether you use Site Recovery Manager with
array-based replication or with vSphere Replication.
For information about how Site Recovery Manager handles datastore tagging for Storage DRS, see
http://kb.vmware.com/kb/2108196.
Using Site Recovery Manager with Array-Based Replication on Sites with
Storage DRS or Storage vMotion
You must follow the guidelines if you use array-based replication to protect virtual machines on sites that
use Storage DRS or Storage vMotion.
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Storage DRS considers the protection and the replication status of datastores while calculating
placement recommendations to perform automatic or manual migration. Storage DRS checks if the
datastore is replicated or not, part of a consistency group or protection group, then tags the datastore
accordingly. For more information on how Site Recovery Manager handles datastore tagging, see
http://kb.vmware.com/kb/2108196.
Chapter 11 Interoperability of Site Recovery Manager with Other Software
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