Enhanced cluster quorum device

Server and Cluster Administration Guide for Hitachi NAS Platform

Version
15.1.x
Audience
anonymous
Part Number
MK-92HNAS010-35

Beginning with release 10.1, an Enhanced Cluster Quorum Device, Quorum Services v2 was introduced. QD v2, hosted on the same system as the NAS Manager, operates in a passive rather than active fashion. It is used only when communication fails between cluster nodes, whereas the previous QD continually polled cluster nodes to detect a node failure. Rather than actively polling the cluster heartbeat, the QD v2 quorum daemon is only called when the server cluster requires an additional quorum vote, in the event of the loss of a cluster node. QD v2 stores node information to elect one node as the master when the cluster experiences a change in the membership. After one node is elected as master, all the remaining nodes will join the master to reconfigure the cluster.

Current NAS Manager versions continue to support servers running 8.x firmware, and the NAS Manager runs instances of both the previous and the new Quorum Device daemons. The firmware version determines the user choice of either the legacy QD, or QD v2. Both are managed from the NAS Manager. Servers running firmware 8.x or earlier can only use the legacy quorum services. Servers running firmware 10.x or later, requiring quorum services, can only use Quorum Services v2. The two Quorum Device daemons communicate with each other for cluster configuration, so that a single cluster cannot be served by both the old and the new QD daemons simultaneously.