Storage Area Network Configurations for RA8000/ESA12000 on Windows NT-Intel Application Note

Application Note
AA–RHH6B–TE Page 23
SAN Fabric Configuration 6 – Four FC Switches, Cascaded Meshed Fabric,
Controller Transparent Failover
Mode
SAN Fabric configuration 6 (Figure 7) is a meshed Fabric cascaded switch configuration that
provides the maximum server and storage connectivity available in a single Fabric. All of the
switches in the Fabric are interconnected providing alternate paths within the Fabric. This Fabric
feature automatically reconfigures a route to a good path should a component in a Fabric path fail. Up
to 40 separate (non-cooperating) servers or up to 20 pairs of clustered (cooperating) servers can be
connected through 4 16-port FC switches to 3 storage systems. With 8-port FC switches up to 16
servers can be connected to 1 storage system. With either switch type the number of storage systems
can be increased if the number of servers is reduced to provide switch ports for storage. A minimum
of 1 ISL is required between each of the 4 switches and a minimum of 2 ISLs are required to cross
couple the 4 switches as shown. Additional ISLs may be required based on the specific server and
storage configuration and count, and the applications utilized The cross-coupled ISLs ensure that the
hop count within the Fabric does not exceed 2 for a single path failure. The ISL(s) can be up to 10 km
allowing connectivity between four remote sites. The HSG80 array controllers within the RA8000 or
ESA12000 storage enclosure are configured in Transparent failover mode providing full controller
redundancy in the unlikely event of either controller failing.
Figure 7 Four Switches, Cascaded Meshed Fabric Configuration Example
Active
ActiveStandby
Standby
Port 1 A Port 2
Port 1 B Port 2
24 Disks
24 Disks
RA8000 or
ESA 12000 FC
Dual Controller
24 Disks
Windows NT
Intel
Server
FC HBA
FC Switch #2
FC Switch #4
FC Switch #1
FC Switch #3
Windows NT
Intel
Server
FC HBA
Windows NT
Intel
Server
FC HBA
NT Cluster
Active
ActiveStandby
Standby
Port 1 A Port 2
Port 1 B Port 2
24 Disks
24 Disks
RA8000 or
ESA 12000 FC
Dual Controller
24 Disks
Active
ActiveStandby
Standby
Port 1 A Port 2
Port 1 B Port 2
24 Disks
24 Disks
RA8000 or
ESA 12000 FC
Dual Controller
24 Disks
Windows NT
Intel
Server
FC HBA
Windows NT
Intel
Server
FC HBA
SHR-1552