Master and Slave Hosts

[jahanzaib]

I got understanding about the Master and Slave concept in HA. But i didn't understand the election process for the master. How the master cluster selected that: :smileyconfused: :smileyconfused:

As per vmware details master Host selected "The host that mounts the greatest number of data stores has an advantage in the election"

What this mean greatest number of datastore? IF we have Shared ISCSI Storage then all Esxi host are attached to that ISCSI storage equally ? :smileysilly:

"When vSphere HA is enabled for a cluster, all active hosts (those not in standby or maintenance mode, or not disconnected) participate in an election to choose the cluster's master host. The host that mounts the greatest number of datastores has an advantage in the election. Only one master host exists per cluster and all other hosts are slave hosts. If the master host fails, is shut down, or is removed from the cluster a new election is held"

[a_p_ · Accepted solution]

HA Master election is actually done by doing a few simple checks, the first one is the greatest number of datastore a hosts has mounted. If multiple hosts have the same number of datastores, the next criteria - the highest Managed Object Id - comes into play. See "Election" at https://ha.yellow-bricks.com/fundamental_concepts.html

André

[jahanzaib]

This is what i need to know what does it mean

" the first one is the greatest number of datastore a hosts has mounted". Greatest Number mean in Bigger Size or number of Datastore mounted to specific host? In my case I have 5 Esxi host mounted to 3 Shared ISCSI Storage. So how the Master selection will happen?

[TomHowarth]

Greatest as in Number of DataStores, but as Andre stated it is just the foremost decision point in a number of decision points.

read the article stated in his reply to gain a greater understanding.