HP StorageWorks Storage Mirroring for Linux User's Guide (T2558-96078, February 2008)

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Failover Options
In order for failover to stand in for a failed machine, you must configure the monitoring and failover options. These options
are the same regardless of the configuration method (Management Console, Failover Control Center, or Text Client) that
you use.
 Source Machine—The machine that is monitored for failure.
 IP Addresses—The machine that is monitored for failure may have one or more IP addresses. When multiple IP
addresses are available, you have the option of monitoring some or all of the addresses as well as failing over for some
or all of the addresses.
 Target Machine—The machine that will be assuming the identity of the source machine in the event that the source
machine fails.
 Target NIC—The network card on the target machine that will receive the traffic from the failed source machine.
 Monitor Interval and Missed Packets—The monitor interval specifies how often the monitor request is sent to the
source machine. The missed packets specifies how many monitor replies can be missed before assuming the source
machine has failed. To achieve shorter delays before failover, use lower monitor interval and missed packets values. This
may be necessary for IP addresses on machines, such as a web server or order processing database, which must remain
available and responsive at all times. Lower values should be used where redundant interfaces and high-speed, reliable
network links are available to prevent the false detection of failure. If the hardware does not support reliable
communications, lower values can lead to premature failover. To achieve longer delays before failover, choose higher
monitor interval and missed packet values. This may be necessary for IP addresses on slower networks or on a server
that is not transaction critical. For example, failover would not be necessary in the case of a server restart.
 Failover IP Addresses—You can specify whether source IP addresses are failed over to the target.
 Manual Intervention—Manual intervention allows you to control when failover occurs. When a failure occurs, a prompt
appears in the Failover Control Center and waits for you to manually initiate the failover process. You can disable manual
intervention if you want failover to occur automatically.
 Scripts—The failover and failback scripts for the target are stored on the target machine, but are unique for each source
machine. The failback script for the source is stored on the source machine. Scripts may contain any valid command,
executable, or batch file.