I’ve seen a lot misinterpretations of the new advanced HA option “das.allowNetwork”. What is this option for and when should I use it or shouldn’t is the most asked question.
So let’s start with a little history, back in the days “pre 3.5 U2″ one could configure a cluster on multiple IP subnets without facing any [...]

Seva, a VMware Technical Account Manager, put together a cool table with the implications of a VirtualCenter crash. This is a follow up to my blog about VirtualCenter getting more important by the minute. I think the most important thing to remember is that the VM’s keep running whatever happens to your VC Server and [...]

I’ve seen this one on the VMTN forum a couple of times. When the Health Status isn’t showing you could do the following to fix it:

Restart VirtualCenter service on the VC Server
Restart mgmt-vmware service on the hosts that are affected (service mgmt-vmware restart)
Restart vmware-vpxa on the hosts that are affected (service vmware-vpxa [...]

There seems to be a lot of fuss about HA not being reconfigured when Update 2 is installed.
The error message that appears:
“HA Agent on <hostname> in cluster <clustername> in <datacenter> has an error Incompatible HA Networks: Host has network(s) that don’t exist on cluster members: <ip address>: Cluster has network(s) missing on host: <ip address>: [...]

A while back I wrote down all the HA advanced options. With ESX 3.5 Update 2 VMware added a couple extra advanced options, this is the complete list:

das.failuredetectiontime - Amount of milliseconds, timeout time for isolation response action(with a default of 15000 milliseconds).
das.isolationaddress[x] - IP adres the ESX hosts uses for it’s heartbeat, where [x] [...]