VMware Disaster Recovery with Site Recovery Manager
VMware provides a dedicated solution for disaster recovery, as part of the vSphere virtualization suite, called VMware Site Recovery Manager (SRM). SRM is a VMware backup automation tool that provides replication technology and supports policy-based management of backup programs. SRM can perform orchestration of recovery programs to minimize downtime in case of disasters, and also lets you run non-disruptive testing of disaster recovery plans. VMware Site Recovery Manager is offered either on-premises or on the AWS cloud, in a Disaster Recovery as a Service (DRaaS) service model.
SRM leverages VMware vSphere Replication to provide hypervisor-based virtual machine replication. It protects VMs from partial or complete site failures by copying the virtual machines from a primary site to a secondary site, or from multiple sources to a single disaster recovery site. VSphere Replication is configured on a per-VM basis, allowing you to control which VMs are duplicated. After the initial replication, vSphere replication performs incremental backup, ensuring only changes are replicated to decrease network bandwidth usage.
How Does VMware Site Recovery Manager Work?
Site Recovery Manager is based on an application server that runs on a Windows server, with its own database and a plug-in that connects it to vSphere clients. Each disaster recovery site must deploy an SRM host and a vCenter server. These servers may be deployed using physical servers or virtual machines. vCenter Server provides central visibility and control of all the SRM servers.
In vSphere Replication, the hypervisor uses a VR agent and a vSCSI Filter to capture writes for a VM’s virtual disk, compress the data, and ship it via a designated network to a VRS service at the recovery site. The VRS services sends the compressed data to an ESXi host via NFC (network file copy), who decompresses it and writes it to disk.
Array-based replication requires storage replication adaptor (SRAs) to be installed on the SRM servers. The SRAs enable SRM to manage (monitor, stop, start, and reverse) the replication and to manage storage-based snapshots.
vSphere Replication, which replicates VMs / virtual disks involves virtual appliances at each site running the vSphere Replication Management Service (VRMS) and vSphere Replication Service (VRS).
SRM has the following additional deployment requirements:
A trusted high-speed network connection between production sites and the disaster recovery site—not a dedicated link—to avoid VPN connections across the Internet
Array-based replication between recovery site and the protected site, using a replication adapter supported by SRM (see a full list).
The recovery site must have access to the same public and private IP networks as the protected site.
The recovery site must have sufficient hardware, storage and network resources to run VM workloads of the protected site.
You must ensure databases and other systems in your protected site are supported by Site Recovery Manager—see the full compatibility matrix.
VMware Site Recovery Manager Best Practices
VMware recommends the following best practices when operating VMware Site Recovery Manager:
The SRM database should be colocated with the SRM server if possible, or as close as possible, to decrease round-trip time of data transfers.
Prefer fewer but larger NFS volumes, to ensure less time is needed to mount the instances. This can also reduce recovery time by letting you define fewer security groups.
Prefer more hosts, enabling higher concurrency when recovering VMs, resulting in faster recovery times.
Before backing up VMs, ensure recovery site hosts are not in standby mode, so they are ready to create placeholder VMs.
Prefer to use the same VM dependencies across priority groups, instead of configuring dependencies per VM.
Install VMware Tools in protected VMs. This will allow SRM to check heartbeats and network performance.
Make sure no custom script or UI dialog box blocks backup retrieval.
Swap files should be stored in a non-replicated datastore, to avoid the need to replicate between two sites and make remote calls to vCenter Server.
By associating multiple SRM servers with a single vCenter Server, you can use SRM to accommodate a shared recovery site or multiple peer sites.You can use SRM to set mappings for resource, folders, and networks. SRM use these mappings to properly place recovered VMs. The sample screenshot contains a common approach, where the source and target networks are mapped using identical names.
You can use SRM to set mappings for resource, folders, and networks. SRM use these mappings to properly place recovered VMs. The sample screenshot contains a common approach, where the source and target networks are mapped using identical names.
You can configure VM protection groups to use in recovery plans. You can use priority groups and dependencies to effectively establish a startup order in a recovery plan. The example recovery plan begins by pre-synchronizing storage, stopping VMs, and synching storage. Perhaps some of the primary data center is still active, so the plan will attempt to perform a final data synchronization and graceful VMs shutdown, if it can.
Regardless, it moves on to steps at the recovery site, such as bringing hosts out of standby, suspending non-critical VMs, preparing virtual disks, and starting VMs by priority group. You use the Run button to perform actual failovers or migrations. You use the Test button to run the plan in a non-disruptive manner, using dedicated networks and (VM or storage based) snapshots. When you are finished with a DR Test, you run Cleanup.
VMware Site Recovery on AWS
VMware provides VMware Cloud on AWS, a hybrid service that enables cloud migration, hybrid data centers and disaster recovery. As part of the service, VMware provides Site Recovery Manager (SRM) as a managed service, in a Disaster Recovery as a Service (DRaaS) model.
VMware Site Recovery enables replication, orchestration and backup automation on AWS to protect cloud applications from failure. It provides an end-to-end disaster recovery solution with two key capabilities:
Multi-site topologies—use one VMware Cloud on AWS Software-Defined Data Center (SDDC) for multiple on-premises sites, reducing costs by consolidating enterprise resources.
One-click deployment and testing of Site Recovery Manager—check connectivity of VMware Cloud on AWS from your on-premise center with one click, and instantly connect local workloads to backup policies.
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