HP StorageWorks Storage Mirroring user's guide (T2558-96073, February 2008)

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10. Highlight an IP address that you have selected for monitoring and select the Missed Packets. This setting is the number
of monitor replies sent from the source to the target that can be missed before assuming the source machine has failed.
This option is not configurable if your
Method to Monitor for Failover is set to No Monitoring. Repeat this step for
each IP address that is being monitored.
11. If you are monitoring multiple IP addresses, highlight the source name and specify the Failover Trigger.
 All Monitored IP Addresses Fail—Failover begins when all monitored IP addresses fail. If there are multiple,
redundant paths to a server, losing one probably means an isolated network problem and you should wait for all IP
addresses to fail.
 One Monitored IP Address Fails—Failover begins when any one of the monitored IP addresses fails. If each IP
address is on a different subnet, you may want to trigger failover after one fails.
NOTE: 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 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.