If you’re running VMware vSphere High Availability (HA) cluster, you have certainly noticed a folder named “.vSphere-HA” on several of your shared datastores. What is VMware .vSphere-HA folder for? This folder has something to do with HA, you think, but what exactly is stored there? You certainly do not want to delete it, do you?

That’s what we will look at today. You can click to enlarge.

This folder resides on shared datastore which is used as a secondary communication channel in HA architecture. This folder has several files inside, and everyone of them has different role:

  • host-xxx-hb files – those files are for the heartbeat datastore. The heartbeat mechanism uses the part of the VMFS volume for regular updates. Each host in cluster has it’s own file like this in the .vSphere-HA folder.

vSphere HA uses datastore heartbeating to distinguish between hosts that have failed and hosts that reside on a network partition. Datastore heartbeating allows vSphere HA to monitor hosts when a management network partition occurs and to continue to respond to failures that occur.

  • protected list file – when you open this file, you’ll see a list of VMs protected by a HA. The master host uses this file for storing the inventory and the state of each VM.
  • host-xxx-poweron files – this files role’s is to track the running VMs for each host of the cluster. The file is read by the master host which will know if a slave host is isolated from the network. Slave hosts uses this poweron file to tell the master host “hey, I’m isolated”. The content of this file reveals that there can be two states: zero or one. Zero = not isolated and One = isolated. If the slave host is isolated, master host informs vCenter.

The .vSphere HA folder is created only on datastores that are used for the datastore heartbeating. You shouldn’t delete or modify those files.

You may also want to read this two VMware Knowledge Base articles: