# Failover hardware requirements

Configuring for failover | Hardware requirements | Installation guidelines and restrictions

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:

- Two ServeRAID-4H
- Two ServeRAID-4M
- Two ServeRAID-4Mx
- Two ServeRAID-4L
- Two ServeRAID-4Lx
- Two ServeRAID-3HB
- Two ServeRAID-3H
- Two ServeRAID-3L
- 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:

- IBM Netfinity EXP15 Rack Enclosure
- IBM Netfinity EXP200 Rack Enclosure
- IBM Netfinity EXP300 Rack Enclosure

## More information

- Failover installation guidelines and restrictions
- Preparing the controllers for failover
- Connecting the enclosures
- Configuring the arrays and logical drives
- Completing the failover environment installation
- Failing from active to passive controller (action)

Glossary | Index | Contents

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