Managing a ‘Master’ VDI Image across multiple sites | Made easy with Nutanix

You are working on a large virtual desktop deployment using Active/Active datacenters, you have multiple use cases and multiple master images. With an Active/Active setup, your users have the possibility of being in DC1 one day, and DC2 the next.

So, what do you do when you have a requirement for the image to be available in case of a site failure? Nutanix make this easy for us, using protection domains and per-VM backups.

What is a protection domain?

A protection domain is a VM or group of VMs that can be backed up locally on a cluster or replicated on the same schedule to one or more clusters. Protection domains can then be associated with remote sites.

It is worth noting that protection domain names must be unique across sites and a VM can only reside in one protection domain.

A protection domain on a cluster will be in one of two modes:

  • Active – Manages live VMs, makes, replicates and expires snapshots
  • Inactive – Receives snapshots from a remote cluster

A Protection Domain manages replication via a Consistency Group.

What is a consistency group?

A Consistency Group is a subset of the VMs within the Protection Domain. All VMs within a Consistency Group will be snapshotted in a crash-consistent manner and have snapshots created at each replication interval.

What is a snapshot?

A snapshot is a read-only copy of the state and data of a VM at a point in time. Snapshots for a VM are crash consistent. This means that the VMDK on disk images are consistent with a single point in time. The snapshot represents the on disk data as if the VM crashed. These snapshots are not however application consistent meaning the application data is not quiesced at the time of the snapshot. With some server workloads this could cause us some issues for recovery, however for our VDI master image this is not an issue – the master image is likely going to be powered off the majority of the time. Snapshots are copied asynchronously from one cluster to another.

What are per VM Backups?

A per VM backup give the ability to designate certain VMs for backup to a different site, such as a group of desktop master images. Not all legacy storage vendors offer the ability to replicate at a VM level, normally an entire LUN or Volume replicated at a single time.

 Where am I going with this?

There are many solutions to replicate data, however Nutanix provides this capability, albeit at a small cost, within its platform. No additional components are necessary and it even has an SRM plugin. The key feature is Nutanix integrates with vSphere to make this is a seamless process.

Andre Leibovici posted a great article Disaster Recovery – Failover and Failback with Nutanix which explains the process and includes a video which is below.

Working with vSphere 5.5 and Nutanix  check out my Nutanix Configuration with vSphere 5.5 post

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