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by Duncan Epping

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16 July, 2010

vSphere 4.1 HA feature, totally unsupported but too cool

Early 2009 I wrote an article on the impact of Primary Nodes and Secondary Nodes on your design. This was primarily focussed on Blade environments and basically it discussed how to avoid having all your primary nodes in a single chassis. If that single chassis would fail, no VMs would be restarted as one of the primary nodes is the “failover coordinator” and without a primary node to assign this role to a failover can’t be initiated.

With vSphere 4.1 a new advanced setting has been introduced. This setting is not even experimental, it is unsupported. I don’t recommend anyone using this in a production environment, if you do want to play around with it use your test environment. Here it is:

das.preferredPrimaries = hostname1 hostname2 hostname3
or
das.preferredPrimaries = 192.168.1.1,192.168.1.2,192.168.1.3

The list of hosts that are preferred as primary can either be space or comma separated. You don’t need to specify 5 hosts, you can specify any number of hosts. If you specify 5 and all 5 are available they will be the primary nodes in your cluster. If you specify more than 5, the first 5 of your list will become primary.

Please note that I haven’t personally tried it and I can’t guarantee it will work.

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Filed Under: BC-DR, Server

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Comments

  1. NiTRo says

    16 July, 2010 at 16:31

    Sounds good for the future !

  2. Andrew Storrs says

    16 July, 2010 at 16:57

    This will be great for blade environments designs (in the future when it’s supported).

  3. Jason Boche says

    16 July, 2010 at 17:58

    Couple this article to your earlier article on how to manipulate AAM to specify more than 5 primary hosts (*also unsupported by VMware*).

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About the author

Duncan Epping is a Chief Technologist in the Office of CTO of the Storage & Availability BU at VMware. He is a VCDX (# 007) and the author of multiple books including "Essential Virtual SAN" and the “vSphere Clustering Technical Deepdive” series.

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