Often, virtual admins have a pressing need to move virtual machines from one host to another without facing application downtime. The reason this scenario arises often is because a particular host may run out of resources due to contention issues with other virtual machines in that same host. vMotion® from VMware® allows for seamless virtual machine migration without any interruptions. Similar to vMotion, with the latest generation of Hyper-V®, Microsoft® now offers Live Migration which provides the capability to move virtual machines flawlessly between several hosts without disruption or application downtime.
Live Migration offers virtual admins plenty of flexibility and several added advantages:
- Enables proactive maintenance. Live Migration offers the ability to perform migration and maintenance of hosts simultaneously. This drastically brings down the migration time giving you plenty of time to plan and simplify Hyper-V mobility.
- Improved hardware utilization. When you have many virtual machines which are only occasionally used, then you can move those virtual machines to either a standalone server or cluster with minimum capacity and the source host can be powered down.
- Performance and flexibility when working in a dynamic environment.
- Rich in features. With the latest Hyper-V, Microsoft offers new APIs to migrate virtual machines across cluster nodes along with functionalities that enable migration of virtual machines in and out of failover clusters without downtime.
Like Live Migration, there are other virtual migration mechanisms that are offered by Hyper-V. These are also used by virtual admins to improve virtual machine availability and performance.
- Live Storage Migration: With Live Storage Migration, IT admins can now move around files and data from virtual machine to another storage location without any service interruption or downtime. For example, several virtual machines in a host are dependent on the same volume and also require high disk I/O, then storage performance will be affected. In turn, all the virtual machines dependent on the same volume will have performance issues. So Live Storage Migration will be useful to move a virtual machine to another host which has more storage capacity.
- Shared Nothing Live Migration: In Shared Nothing Live Migration, IT admins can move a running or a live virtual machine from one host to another. For example, admins can move the virtual machine between hosts even if the virtual machine’s file system resides on a storage device that is not shared by both hosts. This kind of migration is very useful for admins in small and medium organizations who want to perform periodic maintenance on a host during a planned outage.
- Live Migration Queuing: A host can queue up several Live Migrations so virtual machines are lined up one after another to move to the destination host. This is useful when performing several Live Migrations.
- Live Virtual Machine and Storage Migration (VSM): This is a process for migrating virtual machine and the virtual machine storage together from one host to another. VSM is supported between two stand-alone or Hyper-V host clusters. With VSM, IT admins can transfer virtual machines to either a cluster share volume (CSV) or SMB 3.0 file share on the destination host cluster.
Whichever migration method you choose to deploy, the ultimate goal is ensure the end-user or the business isn’t impacted by virtual machine performance issues. One other thing to keep in mind when you’re migrating virtual machines is to look out for performance bottlenecks across your virtual infrastructure and ensure application performance is nowhere near the set threshold limit.