High availability is important when your business requires minimum or no downtime, and planning for it in advance is very important.

Based on what we learned about each component, we now need to plan the high availability (HA) for each VMM component.

Start by planning the HA for the core component, followed by every VMM component of your design. It is important to consider hardware and other System Center components, as well as the OS and software licenses.

When planning for highly available VMM management servers, you should first consider
where to place the VMM cluster. As per best practices, the recommendation is to install
the VMM cluster on a management cluster, preferably on some physical servers, if using converged network for your virtual network. However, if you plan to install highly available VMM management servers on the managed cluster, you need to take into consideration the following points:

• Only one highly available VMM management server is allowed per Failover Cluster.
• Despite the possibility to have a VMM management server installed on all cluster nodes, only one node can be active at a time.
• To perform a planned failover, use Failover Cluster Manager. The use of the VMM console is not supported.
• In a planned failover situation, ensure that there are no running tasks on the VMM management server, as it will fail during a failover operation and will not automatically restart after the failover operation.
• Any connection to a highly available VMM management server from the VMM console will be disconnected during a failover operation, reconnecting right after.
• The Failover Cluster must be running Windows Server 2016 in order to be supported.
• The highly available VMM management server must meet system requirements. For information about system requirements for VMM, see the Specifying the correct system requirements for a real-world scenario recipe in this chapter.
• In a highly available VMM management deployment, you will need a domain account to install and run the VMM management service. You are required to use distributed key management (DKM) to store the encryption keys in Active Directory.
• A dedicated and supported version of Microsoft SQL Server should be installed. For supported versions of SQL Server for the VMM database, see the Specifying the correct system requirements for a real-world scenario recipe.

The following sections are the considerations for SQL Server and the VMM library in an
HA environment.

In an enterprise deployment of VMM, it is recommended that you have a SQL Server cluster to support the HA VMM, preferably on a cluster separated from the VMM cluster. VMM 2016 supports SQL Server Always On Availability Groups. The following link will show you a good example of how to set it up: See the Configure SQL Server with AlwaysOn AGs recipe in Chapter 3, Installing VMM 2016.

As it is the best practice in an enterprise deployment, a highly available file server for hosting the VMM library shares is highly recommended as VMM does not provide a method for replicating files in the VMM library, and they need to be replicated outside of VMM.

As a suggestion, you can use the Microsoft Robocopy tool to replicate the VMM library files if you have distributed the library type.