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Failback is an SRM term that describes the ability to perform a subsequent disaster recovery or planned migration after a successful recovery and reprotect. The benefit that failback introduced in SRM 5.x is the automated ability to move back and forth between sites with minimal effort. This capability facilitates several use cases including the ability to run production applications at the disaster recovery site, resource balancing, and improved disaster recovery infrastructure ROI.
Note: Before running the Failback recovery plan, run a test recovery of the plan.
Asynchronous replication for vVol based VMs
Introduction
Since PowerStoreOS 3.0 supports VASA 3.0 native storage based asynchronous replication for vVol based VMs. This feature uses VMware Storage Policies and requires VMware Site Recovery Manager instances in both sites. The following section gives a brief overview how vVol replication is implemented in PowerStoreOS. Please also refer to PowerStore VMware integration White Paper for vVol based VMs or VMware Site Recovery Manager product documentation.
Licensing
Asynchronous replication of vVol based VMs is included at no extra cost for supported PowerStore clusters.
Theory of operation
The configuration of asynchronous replication for vVol based VMs requires a remote system pair as describe in an earlier section configured for two PowerStore Model T clusters running PowerStoreOS 3.0 or later. Each of the PowerStore Clusters for vVol replication needs registration in vCenter as a storage provider and VASA 3.0 API is used to exchange information between PowerStore Cluster and the associated vCenter. The VMware Storage Policy which could be assigned to VMs in vCenter leverage the same replication rules in PowerStore Manager as used for other PowerStore asynchronous replications. Asynchronous replication for vVol based VMs also use the same snapshot based async replication technology as native block replication which is described in section native asynchronous block replication. Once a VMware Storage Policy with PowerStore replication is assigned to a vVol based VM, a replication session is created on PowerStore for VM vVol resources in the same resource group. VMware resource groups can be selected when a VMware Storage Policy is configured for a VM. VMware SRM uses these VMware resource groups to manage the protected VMs in Replication Groups. A SRM Recovery Plan controls the PowerStore replication session for vVols in a replication group during test failover, failover, and reprotection. After a VM has a VMware Storage Policy assigned, and the Resource Group is in a Replication Group with Protection Plan in SRM a placeholder VM on destination vCenter and PowerStore is created. The storage container for placeholder VM is part of the site pair configuration in SRM.
Supported replication flows
For replication of Resource Groups on PowerStore different combinations of source- and destination vVol Storage Container are possible.
One or more different Resource Groups on a single Storage Container to different Storage Container on different PowerStore clusters
Resource Groups from Storage Containers on different PowerStore clusters to a single Storage Container
Multiple replications in different directions
Combinations of all above
Supported replication flows
Replication Operations
The main operations for a protected VM’s are available in VMware SRM only. This section gives an overview of available Operations in PowerStore Manager and VMware Site Recovery Manager.
vVol replication operations in PowerStore Manager
Operations on for a replication session in PowerStore Manager always affecting all vVols in the same resource group. A resource group is configured during the protection of a VM when assigning the VMware Protection Policy in vCenter.
Synchronize
With Synchronize operations a manual replication is executed for all vVols in the replication group covered by the replication session.
Pause
This operations pauses the replication session for all vVols in the replication group at the current state. After pausing a vVol replication session the scheduled RPO replications are disabled.
Resume
The resume operations resume a paused replication as it was when pausing the replication session and enables the schedules for RPO based replications.
vVol replication operations in VMware SRM
All vVol replication operations in SRM are based on a underlaying Replication Group. Each Replication Group can contain multiple resources groups.