Computer Drive User Manual

Chapter 31. IBM TotalStorage Productivity Center for Replication 485
Figure 31-11 LSS heartbeat triggers freeze when connectivity to server fails
Figure 31-11 implies a failing connectivity between the RM server and a primary storage
server. Once this heartbeat is set and the storage subsystem cannot communicate its
heartbeat information to the RM sever, the storage server internally triggers a freeze to its
involved LSSs and their primary volumes. Because this heartbeat is a timer-scheduled
function, it is based on the Consistency Group time-out value of each LSS that contains
volumes that belong to the concerned session. This session-based heartbeat timer expires
after the lowest time-out value of all concerned LSSs.
With more than one storage server involved, the RM server issues freeze commands to all
other LSS pairs in the affected session once the heartbeat expired and the RM server could
not receive heartbeat information from any one of the involved storage servers.
The disconnected storage server or LSS resumes I/O after the Consistency Group time-out
has expired. LSSs or storage servers that may still be connected to the RM server receive a
corresponding freeze command from the RM server followed by a run command when a
freeze-and-go policy has been selected.
Note that Extended Long Busy (ELB), automation window, and freeze period are synonyms
for Consistency Group time-out in the above context.
31.13 Supported platforms
The TPC for Replication server can currently run under the following operating systems:
򐂰 Windows 2003 Server Edition with SP1
򐂰 Windows 2003 Enterprise Edition SP1
Replication Manager Server
LSS
LSS
LSS
LSS
LSS
SecondariesPrimaries
Session
FREEZE
1
2
LSS
FCP ports
Ethernet ports
PPRC FCP links