Application Note
AA–RHH6B–TE
Page
13
SAN Fabric Configuration 2 – Two FC Switches, High Availability, Secure Path,
Controller Multiple-Bus Failover Mode,
Integrated EBS
SAN Fabric configuration 2 (Figure 3) is a high availability storage configuration that uses two
separate Fabrics to provide two data paths between servers and disk storage configured in Multiple-
Bus failover mode. Tape storage can be configured on one of the Fabrics to provide backup and
restore capabilities. Up to 15 separate (non-cooperating) servers or up to 7 pairs of clustered
(cooperating) servers can be connected through two 16-port FC switches with 1 storage system. With
8-port FC switches up to 6 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. This SAN configuration utilizes the high availability features of controller Multiple-
Bus failover and Compaq Secure Path for Windows NT software. With 2 FC HBAs in each server,
and 2 FC switches, a second separate path to the storage is provided to each server. The 2 switches
form isolated Fabrics providing the highest level of storage path fault tolerance should a failure occur
with any path component - FC HBA, FC Switch, Fabric path interconnect, or storage controller. Non-
HA configured servers and storage configured in Transparent Failover Mode are supported in this
configuration, however access may be limited to one or the other of the two Fabrics unless 2 FC
HBAs are utilized, each connected to a different Fabric.
Figure 3 Two Switch HA Fabric Configuration Example
SAN Configuration 2 Server/Storage Connectivity Rules
•
Any mix of Windows NT Intel Servers - standalone or clustered, configured for HA or non-HA,
and any mix of Multiple-bus Failover and Transparent Failover storage systems using these
maximums. Assumes all servers configured for HA, 2 FC switches and 2 FC HBA’s per server,
an even storage port count, and no EBS ports.
SHR-1428
Windows NT
Intel
Server
FC HBA 1 FC HBA 2
Windows NT
Intel
Server
Windows NT
Intel
Server
FC Switch #1
24 Disks
24 Disks
RA8000 or
ESA12000 FC
Dual Controller
24 Disks
Port 1 A Port 2
Port 1 B Port 2
. . . .
Active
Active
Active
Active
FC HBA 1 FC HBA 2
FC HBA 1 FC HBA 2
FC Switch #2
Windows NT
Intel
Server
FC HBA 1 FC HBA 2
