In addition to the mappings, SRM requires assigning a placeholder datastore at each site. The datastore holds the configuration files for the placeholder, or shadow, virtual machines at the recovery site. VMware recommends using a non-replicated datastore as these placeholder VMs can be re-created by SRM if they are lost or accidentally removed. Typically, only one placeholder datastore per site is required, though more may be configured if wanted. Dell Technologies recommends configuring two for redundancy. The placeholder datastore need only be large enough to hold the configuration files for all the recoverable virtual machines. It is not a significant amount of storage, though it is perfectly acceptable to use large, existing datastores that have VMs in them. Also note that the placeholder datastores do not have to be backed by PowerFlex volumes, they only have to be available to the SRM ESXi hosts.