HP Storage Mirroring V4.5 Software - Manual (Page 58)

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Monitor settings
The Monitoring tab includes options for configuring how you want to monitor the source server for
failure.
Configure how you want to monitor the source server for failure.
1. Select the Active Monitoring Enabled option to enable or disable failover for the selected
source/target pair.
2. By default, Manual Intervention Required is selected. Manual intervention allows you to
control when failover occurs. When a failure occurs, a prompt appears and waits for you to
initiate the failover process manually.
Disable Manual Intervention Required only if you want failover to occur immediately when a
failure condition is met.
3. In the Method to monitor for Failover field, select the ping method to use when monitoring
source IP addresses.

Network Access (ICMP)—Storage Mirroring failover uses ICMP pings to determine if the
source server is online. If a network device, such as a firewall or router, between the source
and target is blocking ICMP traffic, failover monitors cannot be created or used.

Replication Service (UDP)—The Storage Mirroring service on the target server sends a
ping-like UDP request to the source Storage Mirroring service, which replies immediately to
confirm it is running. This method is useful when ICMP is blocked on routers between the
source and target.
4. Configure how long to wait after a source failure to initiate failover. The amount of time before
failover begins is calculated by multiplying the Monitor Interval by the Missed Packets. For
example, if the Monitor Interval is set to 5 seconds and the Missed Packets setting is 5, a failover
condition will be identified after 25 seconds of missed source activity.
a. In the Monitor Interval field, select how often the monitor should check the source
machine availability (Default = 5 seconds).
b. In the Missed Packets field, select how many monitor replies can be missed before
assuming the source machine has failed (Default = 5 missed replies).
5. If you are monitoring multiple IP addresses, select one of the Failover Trigger options.

All Monitored IP Addresses Fail—Failover begins when all monitored IP addresses fail.

One Monitored IP Address Fails—Failover begins when any of the monitored IP addresses
fail.
NOTE: In a cluster environment, make sure to include a cushion to account for the time it
takes for SQL to failover between nodes. Setting values too low will cause the
Application Manager to assume the source cluster has failed and will indicate that a
failover condition has been met.