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StoreVirtual Quroum

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Renegade_34g
Occasional Visitor

StoreVirtual Quroum

Hello all, I have a question about my StoreVirtual environment regarding the quroum and failover manager. My environment consists of two StoreVirtual SANs that has a VMware VM Failover Manager. So I have 2 managers and a failover manager. I have been going over the PDF document "HP StoreVirtual Storage User Guide" and on page 121 under "Managers and quorum" section it states this:

Managers use a voting algorithm to coordinate storage system behavior. In this voting algorithm,
a strict majority of managers (a quorum) must be running and communicating with each other for
the LeftHand OS software to function. An odd number of managers is recommended to ensure that
a majority is easily maintained. An even number of managers can get into a state where no majority
exists—half of the managers do not agree with the other half.

My question is, if the FOM crashes or a connection lose happens, will this cause issues and cause this split-brain to happen?

 

 

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oikjn
Honored Contributor
Solution

Re: StoreVirtual Quroum

As long as the other two nodes stay online you will NOT run into a split brain solution.  When the two nodes are online and talking to eachother, they would have two of the three quorum votes wich is >50% of the votes and that would tell them that they are the majority.

 

You will lose quorum if you have a two-node system with a FOM and run into an issue where the FOM goes offline AND one of the nodes goes offline or there is a communication failure between the two nodes.  In that case, there would only be one voting member talking to itself and since one of three is less than 50%, it would assume it was the minority side of the cluster and stop serving IO to prevent it from causing data corruption since it has to assume that the other two nodes are potentially online somewhere serving data.

 

Make sure you don't have that FOM hosted on a LUN served by the cluster.

Renegade_34g
Occasional Visitor

Re: StoreVirtual Quroum

Thank you. This makes better sense now.