3-21
Installing the DuraStor Storage Subsystem
Active-Passive Dual-Port Mode
This operating mode provides redundancy, transparent failover
and failback, and support for optional upstream failover. It is
suitable when a single host computer needs access to all LUNs.
However, this mode has lower performance than active-active
single-port mode. It requires third-party software if upstream
failover is implemented and it reports all arrays twice to the
operating system, causing the potential for data overwrites.
Because this operating mode does not provide any special advantages,
we recommend using active-active single-port mode instead.
1
Connect the SCSI data cables as shown in
Figure 3-19
.
Figure 3-19 Active-passive Dual-port Cabling Diagram
Note:
External terminators are required for any dual
controller configuration where Host 2 In (CH 0),
Host 1 In (CH 3), Disk CH 1, or Disk CH 2 are not cabled.
2
Set the host system HBAs to SCSI ID 7. Refer to your host
system’s user’s guide for details on setting HBA SCSI IDs.
3
Power on the DuraStor External Storage Subsystem. See
page 3-54
.
4
Set the controller operating mode. For detailed instructions, refer to
the user’s guide for the storage management tool you are using.
Host Computer
HBA 1
(ID 7)
HBA 2
(ID 7)
3-meter
cable
3-meter
cable
DuraStor SCSI RAID Appliance
Disk CH 2
Disk CH 1
Serial A
Serial B
Ext
Int
HOST 1 IN (CH 3)
HOST 2 IN (CH 0)
HOST 1 OUT
HOST 2 OUT
HOST 2 IN (CH 0)
HOST 1 IN (CH 3)
DuraStor IUG.book Page 21 Wednesday, January 30, 2002 10:49 AM
