Site Recovery Manager (SRM) and vStorage APIs for Array Integration (VAAI) work together to enhance the efficiency and performance of disaster recovery operations in a VMware vSphere environment. Let’s walk through an example of how SRM and VAAI work together during a failover scenario:

Assumptions:

• You have a primary site (Site A) with critical virtual machines (VMs) running on a vSphere cluster.
• You have a secondary site (Site B) with vSphere hosts and storage, which is set up as a disaster recovery site.
• Both the primary and secondary sites have compatible storage arrays that support VAAI.

1. Configuring SRM and VAAI: Before you can utilize SRM and VAAI together, you need to set up both technologies:
   • Install and configure SRM on both the primary and secondary sites.
   • Create a replication partnership between the primary and secondary sites to enable storage replication between the arrays.
   • Ensure that both the primary and secondary storage arrays support VAAI and are properly configured to leverage its capabilities.
2. Creating Recovery Plans: In SRM, you create recovery plans that define the sequence of steps to be taken during a failover. Recovery plans include protection groups that organize VMs based on their recovery requirements.
3. Performing a Failover: Let’s assume that a disaster occurs at the primary site (Site A), and you need to perform a failover to the secondary site (Site B) to ensure business continuity.
   • When you initiate the failover through SRM, it instructs the storage array at Site B to use VAAI to perform a Full Copy of the virtual machine data from Site A to Site B.
   • VAAI’s Full Copy feature allows the storage array at Site B to efficiently transfer the entire VM data to the appropriate storage location without the need for ESXi hosts at either site to handle the bulk data transfer.
   • Once the Full Copy operation is complete, SRM proceeds to power on the virtual machines at the secondary site. Since the VMs’ data is already available on the storage array at Site B, the failover process is expedited.
4. Improved Failover Performance: By leveraging VAAI’s Full Copy feature during the failover, SRM significantly reduces the time required to replicate VM data from the primary to the secondary site. This results in faster recovery times and minimizes downtime for critical applications.
5. Reduced Impact on Production Site: During the failover, since the bulk data transfer is handled by the storage array at Site B (using VAAI), the production ESXi hosts at Site A are relieved of this task. This reduces the impact on production workloads during the failover process.
6. Rollback and Cleanup: Once the primary site (Site A) is restored, and the disaster is resolved, you can use SRM to initiate a failback to restore VMs to their original location. Again, VAAI can be leveraged to expedite the Full Copy of VM data from Site B to Site A.

In this example, SRM and VAAI work together to provide efficient and automated disaster recovery, improving the performance of replication, and reducing the impact on production systems during failover and failback operations. Together, they help organizations achieve their recovery objectives and maintain business continuity in the face of disasters.