Why no shadowing for a Quorum Disk?
Stated simply, Host-Based Volume Shadowing uses the Distributed Lock Manager (DLM) to coordinate changes to membership of a shadowset (e.g. removing a member). The DLM depends in turn on the Connection Manager enforcing the Quorum Scheme and deciding which node(s) (and quorum disk) are participating in the cluster, and telling the DLM when it needs to do things like a lock database rebuild operation. So you can’t introduce a dependency of the Connection Manager on Shadowing to try to pick proper shadowset member(s) to use as the Quorum Disk when Shadowing itself is using the DLM and thus indirectly depending on the Connection Manager to keep the cluster membership straight—it’s a circular dependency. So in practice, folks simply depend on controller-based mirroring (or controller-based RAID) to protect the Quorum Disk against disk failures (and dual-redundant controllers to protect against most cases of controller and interconnect failures). Since this disk unit appears to be a singl
Related Questions
- In a 2 node cluster, what happens if both nodes lose the heartbeat but they can still see the quorum disk? Don they still have quorum and cause split-brain?
- Is quorum disk/partition reserved for two-node clusters, and if not, how many nodes can it support?
- How is the quorum information located on the system disk of each node kept in synch?
