Operating System Software User Manual

No Communication on the Part of Quorum Witness with Site 1 and Site 2
In a dual-network communication failure resulting in no communication between the quorum witness
and site 1, and between the quorum witness and site 2 (see Figure 59 (page 148)):
• HP 3PAR StoreServ array A and B have both lost connectivity with the quorum witness.
• Remote-copy links are operational, and the HP 3PAR StoreServ arrays are aware of each
other’s operational state.
• A failover does not take place:
Host I/O continues to go to source volumes.◦
◦ Replication of I/O across remote-copy links continues as usual.
Figure 59 No Communication on the Part of Quorum Witness with Site 1 and Site 2
No Communication among Quorum Witness, Site 1, and Site 2
In a triple-network communication failure such that there is no communication among Quorum
Witness, Site 1, and Site 2 (see Figure 60 (page 149)):
• StoreServ A would be unable to update the quorum witness in the context of the failure of the
RC links, and would expect an operational HP 3PAR StoreServ array B (with connectivity to
the quorum witness) to fail over to source. Consequently, HP 3PAR StoreServ array A would
perform a failsafe operation to become a target site, in order to avoid the potential for both
systems to serve host I/O.
• Similarly, HP 3PAR StoreServ array B, which now has no view of either the quorum witness
or HP 3PAR StoreServ array A, cannot know whether HP 3PAR StoreServ array A is operational,
and therefore remains the target.
• A failover takes place:
StoreServ A performs a failsafe operation to become the target.◦
◦ StoreServ B is already, and remains, the target.
◦ Host I/O is stopped.
◦ Replication of I/O across RC links stops.
148 HP 3PAR Peer Persistence with Transparent Failover