IBM ServeRAID-4 Ultra160 Series, 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 NT 4.0 or Microsoft Windows 2000. The latest version of the
ServeRAID device drivers includes fault tolerant technology. With fault tolerance,
you can pair two controllers and connect them to the same enclosure in order to
provide access to the disk, even after one controller fails.
Hardware requirements
Important
To perform fault tolerance, you must use only matched pairs of controllers. The controllers
must be identical, including the level of BIOS and firmware on the controllers.
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 fault-tolerant pair.
In order to use fault tolerant technology with ServeRAID controllers, you must use
one of the following enclosures:
v
IBM Netfinity EXP15 Rack Enclosure
v
IBM Netfinity EXP200 Rack Enclosure
v
IBM Netfinity EXP300 Rack Enclosure.
Installation guidelines and restrictions
Important
If any of the following restrictions and guidelines is not met, failover is disabled for the
controller pair and an error explaining the problem is logged in the system event log. To
verify that the configuration is OK, start the ServeRAID Manager program on the Windows
NT or Windows 2000 server. The Main Tree of the ServeRAID Manager displays controller
pairs that are configured for failover correctly.
In order to achieve fault tolerance with ServeRAID, you must adhere to the
following guidelines and restrictions.
v
The stripe-unit size and firmware level must be the same on both controllers.
v
A fault-tolerant pair cannot be part of a Microsoft Cluster Service shared cluster.
v
You must configure all logical drives on the controller as write through.
© Copyright IBM Corp. 2001
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