2 IBM Netfinity EXP300 - Type 3531 Hardware Maintenance Manual
Clustering support
Clustering is a feature of the expansion unit. Clustering is a means of sharing SCSI
buses and disk drives among SCSI controllers to provide redundancy of SCSI
controllers and servers. This redundancy is important if a hardware component fails.
If a hardware component fails after clustering has been set up, another server will
take ownership of the disk drives or SCSI bus.
The IBM Netfinity EXP300 supports twin-tailed clustering. With twin-tailed
clustering, you can connect two IBM ServeRAID
®
controllers to an EXP300 expansion
unit. In the twin-tailed clustering environment, you can use dual-host controllers
cabled separately to the EXP300 expansion unit; however, only a single logical bus of
13 drives is supported. Each SCSI device on a SCSI bus must have a unique ID. To
prevent conflicts in a twin-tailed configuration, do not install a drive in the bay that
uses SCSI ID 6 because your secondary SCSI ServeRAID controller is set to 6.
Service tip: If you use IBM ServeRAID controllers in a cluster configuration, the
termination power LED on the back of the expansion unit is useful. The ServeRAID
controller provides the signal for termination power. If the termination power LED is
not lit, it indicates that a particular EXP300 expansion unit is not attached to a
controller that is turned on. Make a note of which EXP300 expansion unit is attached
to which server before the hardware is serviced.
Clustering requires additional hardware and specialized software. For more
information, visit the IBM Netfinity Cluster Solutions Web site at:
http://www.ibm.com/pc/us/netfinity/clustering
General
• Modular components:
— High-capacity disk
drives
— Environmental services
monitor (ESM) boards
— Power supplies with
built-in fans
• Technology:
— Supports disk array
technology
— Supports clustering
— SCSI (Ultra160) host
interface
— Redundant data storage,
power and cooling
system, and ESM boards
— Hot-swap technology for
drives, power supplies
with built-in fans, and
ESM boards
•User interface:
— Built-in power, activity,
and fault indicators
— Identification labeling
on customer replaceable
units (CRUs) rear
indicator lights,
switches, and connectors
— Easy-to-replace drives,
power supplies, ESM
boards, and fans
Disk drive storage
• Current capabilities:
— Maximum drives per
expansion unit: 14
— Drives per SCSI bus: 7
— SCSI buses per unit: 2
— SCSI buses can be
configured as one
continuous SCSI bus.
ESM boards
• Technology and interfaces:
— SCSI: Ultra160
— SCSI bus interface: Two
68-pin, Very High
Density Connector
Interface (VHDCI)
connectors for SCSI bus
cables
