Data Replication Manager Windows-Based Server with Single Host Bus Adapter - Application Notes

Additional Considerations
Application Notes – Data Replication Manager Windows-Based Server with Single Host Bus Adapter 13
• Number of hops between the server and the host port 2 of the HSG80s.
NOTE: Only one hop may be a long distance hop.
It is common practice to spread the number of servers equally over the number of FC switches. Host
port 1 of top and bottom controllers in an HSG80 controller pair must be connected to different
switches (if available) to increase the availability of the total solution.
No Single Point of Failure (NSPOF) Configurations
The SPOF within the basic single FC HBA solution are:
• The FC HBA within the server
• The fiber optic cable running between the server and the FC switch
• The GBIC that connects the cable to the FC switch
• The FC switch on the local site
• The ISL
• The FC switch on the remote site
One possible configuration that overcomes the first three SPOF (FC HBA, fiber optic cable, GBIC) is a
cluster of two servers, as shown in Figure 8. If any one of these three components (HBA, cable, GBIC)
fails, the cluster member loses access to the storage, but the application fails over to the other cluster
node and processing continues. An additional advantage of this setup is that the server itself is no
longer a SPOF.
Upon a failure, the FC switch sends an SNMP trap as soon as it detects a "no light" condition on a port.
The FC switch must be equipped with a redundant power supply to increase its availability.
Figure 8: Cluster of two single-FC HBA servers
Production Server
W2K or NT4
HBA
FC Switch
HSG80 Controllers
Production Server
W2K or NT4
HBA
Microsoft Cluster
CXO7869A
ISL