IBM ServeRAID, User Reference

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Chapter 6. Configuring two ServeRAID controllers in a failover
environment
You can configure two ServeRAID controllers in a failover environment when using
Microsoft Windows 2000 or Microsoft Windows NT 4.0. This ServeRAID release
includes an optional ServeRAID device driver that provides fault-tolerance. With
fault tolerance, you can pair two controllers and connect them to the same
enclosure to ensure access to the physical drives, even after one controller fails.
Hardware requirements
Important
To implement fault tolerance, you must use only matched pairs of controllers. The
controllers must be identical, including stripe-unit size and the level of BIOS and firmware
code.
You can use the following pairs to provide fault tolerance:
v Two ServeRAID-4H
v Two ServeRAID-4M
v Two ServeRAID-4Mx
v Two ServeRAID-4L
v Two ServeRAID-4Lx
v
Two ServeRAID-3HB
v
Two ServeRAID-3H
v
Two ServeRAID-3L
v
Two ServeRAID-II
Note: If your system has a built-in ServeRAID controller on the system board, you
cannot use the built-in controller in the failover pair.
To use fault-tolerant technology with ServeRAID controllers, you must use one of
the following enclosures:
v IBM Netfinity EXP15 Storage Enclosure
v IBM Netfinity EXP200 Storage Enclosure
v
IBM Netfinity EXP300 Storage Enclosure
Note: You can configure only 13 physical drives in an EXP300 enclosure.
Installation guidelines and restrictions
Important
If the following guidelines and restrictions are not met, failover is disabled for the controller
pair, and an error explaining the problem is logged in the system event log.
To achieve fault tolerance with ServeRAID controllers, you must adhere to the
following guidelines:
v You must configure the controllers as an active-passive pair, where all logical
drives are defined on only the active controller.
© Copyright IBM Corp. 2002
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