Appendix G: Management group quorum consideration 109
Appendix G: Management group quorum
consideration
If you are deploying a two-node system, OneView InstantOn displays the Quorum Setting field on the
Settings screen. You must enter an NFS file share as the Quorum Witness for the StoreVirtual
management group.
Within a management group, managers are storage systems that govern the activity of all the storage
systems in the group. 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 to ensure the management group functions. An odd number of managers is recommended to
ensure that a majority is easily maintained. An even number of managers can result is a state where no
majority exists and potentially make the management group unavailable. Quorum Witness is the method
to maintain quorum in a 2-node system. For more information, see "Working with managers and quorum"
in
HPE StoreVirtual Storage User Guide
found on the Hewlett Packard Enterprise website
http://www.hpe.com/storage/docs/storevirtual
When you expand a 2-node cluster with Quorum Witness to 3 nodes, the Quorum Witness is no longer
required.
The following table shows how quorum is configured by OneView InstantOn during deployment or
expansion of a management group depending on the number of hosts.
Resultant number of
nodes in cluster
Quorum Witness
Virtual Manager
Number of Regular
Managers
2
Yes
Not applicable
2
2
Not applicable
1
Yes
2
2
3
No
No
3
4
No
No
3
5
No
No
5
>5
No
No
5
1
When deploying a 2-node system, if OneView InstantOn is unsuccessful in connecting to the NFS file share, a virtual
Manager is installed on the management group. In a 2-node system, the quorum Witness is considered the best
method for maintaining high availability in the management group.
2
After deployment, open the StoreVirtual CMC to verify the type of manager configured. If needed, use the
StoreVirtual CMC to configure the management group with the quorum witness.
