I'm generally a networking guy but I'm trying to learn VMware. I'm running two ESX 3.x servers with virtual center. I know that it is possible to create redundancy or high availability by configuring a clustered environment. For HA to work, both ESX hosts must mount to the same datastore on SAN. When one ESX host goes down, the other ESX can take over the VM. How do I configure the second ESX 3.5 server to mount on to an existing VMFS datastore? Could someone explain the configuration steps?


  • You should probably be using a more current version. vSphere 5.5 is the latest AFAIK and the "enterprise" features, such as HA are available for 60 days IIRC. – joeqwerty Mar 22 '14 at 0:29
  • I do have the current vSphere 5.x, but the organization I'm currently employed at are still using ESX for legacy applications. – user256070 Mar 22 '14 at 0:34
  • What do you mean legacy applications? I'm assuming you're referring to the VM's, correct? How do these legacy VM's relate to the hypervisor edition/version? Do you have VM's that aren't supported on vSphere 5.5 for some reason? – joeqwerty Mar 22 '14 at 0:38

VMware HA works if the hosts can see the same storage. What may help to understand is that VMFS is a cluster file system. So being cluster-aware, you can expose a LUN to one or more hosts.

The path of least resistance here is to look at the configuration of one host and duplicate/reproduce it on another.

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