SRM placeholder datastore design

By | January 26, 2015

Recently I was doing a VMware project with 14 HA Clusters (DC) and 8 HA Clusters (DRC) . During the design considerations I wondered how many datastores should be created for Site Recovery Manager (SRM)  placeholders. The placeholder is a file which holds configuration information corresponding to the Protected virtual machines.

Following VMware documentation placeholder datastores must meet certain criteria:

  • for clusters, the placeholder datastores must be visible to all of the hosts in the cluster.
  • you cannot select replicated datastores as placeholder datastores.

When we design placeholder datastores, generally we have 3 options:

  • dedicated placeholder datastore for cluster HA.
  • shared placeholder datastore across clusters HA.
  • 2 SRM placeholders datastore: 1 for each site.

If you have only one cluster HA per site, the answer is simple: one placeholder datastore for site.  So what if you have more clusters? It depends on (e.g. size of infrastructure) - there is no technical limitation to share datastores across clusters so  I create shared placeholder datastore because it is easier for administering. Sometimes creating shared datastores is limited e.g. the project I mentioned at the beginning of this article - I have a customer where sharing datastore across cluster is prohibited (security regulations).

Note: I have met SRM configuration with placeholders located at the same datastore with VM files! Of course it is NOT RECOMMENDED but also possible configuration...


Author: Mariusz

Architect (~ 15 years experience based on passion...) with strong background as a System Administrator and Engineer. Focused on Data Center Solutions: Virtualization/Cloud Computing and Storage/Backup Systems. Currently living in Poland.