High Availability Software for the Intel® NetStructureTM ZT 4901 Technical Product Specification 129
RH Switchover on OS Crash GThe High-Availability RH architecture enables the system master board to perform a switchover to
the backup host in the event of a system crash.
Under the Linux* operating system the RH Software patches the Linux kernel to perform a
switchover whenever a kernel panic occurs. In addition, the host board can be forced to reboot
under these circumstances by simply adding the string “panic=1” in the append statement found in
the lilo.conf configuration file.
Under the VxWorks* operating system this same switchover/reboot functionality is attached to the
NMI interrupt handler. To force a system s witchover and reboo t under VxWo rks, you can configure
the ZT 5524 watchdog timeout to force an NMI interrupt to be generated. This for ces t h e mod if ied
NMI handler to be activated in the event that the ZT 5524 watchdog is not strobed in a suitable
amount of time. This causes a switchover and reboot of the failed host to occur. See the Intel®
NetStructure™ ZT 5524 System Master Processor Board Technical Product Specification for
information about configuring the watchdog/NMI interrupt. For more information on obtaining
documentation, see Section H.2, “User Documentation” on page131.