isolationAddress

[dmeyner22]

I have a 8 Node vSAN cluster and I'm in the process of configuring HA after setting up vSAN.  The question I have is about the isolation address, since HA goes over the vSAN network.  Most of the reading I have done suggest to use an IP address on the vSAN network to prevent HA from using the default gateway on the management network.

So the question is: Do I set the isolationAddress to an available address on the vSAN subnet? or just use the default HA set

[TheBobkin]

Hello dmeyner22​,

"Most of the reading I have done suggest to use an IP address on the vSAN network to prevent HA from using the default gateway on the management network."

Yes correct, use an IP on the vSAN network as the isolationAddress.

depping explains the rationale behind this extremely well here:

vSphere HA heartbeat datastores, the isolation address and vSAN - Yellow Bricks

Bob

[chris122686]

On a regular basis HA contacts its isolation response address to ensure the cluster is functioning correctly. The default isolation response address is the default gateway but other reliable IP addresses can be configured along with the default gateway or the default gateway can also be disabled as an isolation response address.

This issue can occur when HA does not receive a response from all of its configured isolation response addresses.

To resolve this issue, investigate your network to determine why HA is unable to receive a response from at least one isolation response address.

Note:

• If the isolation response address was manually added using the advanced setting das.isolationaddressremove the non-pingable isolation address from your advanced settings and specify a new pingable isolation address.
• When the listed ip address is the currently configured default gateway, add an additional isolation address using das.isolationaddress and disable the use of the default gateway for isolation verification using the advanced setting das.usedefaultisolationaddress set to false.

Please mark this as correct if this answers and helps you .