HP Storage Mirroring V5 Software - Manual (Page 139)

11 - 5
Failover Hardware Configurations
Failover can be configured to stand in for one or more IP addresses associated with different NICs on the source. Each IP
address can be added to a specific target NIC making NIC configuration very flexible. Following are some sample
configurations.
Single NIC on the source and target
A single NIC on the source may have one or more IP addresses assigned to it. If that source or the NIC fails, all traffic from
the source is directed to the target. If there are multiple IP addresses on one source or if there are multiple sources, the target
has to assume traffic from all of the addresses.
Multiple NICs on the source and single NIC on the target
Multiple NICs on the source can increase the impact on the target in the event of a single NIC failure. Using failover monitoring
options, network administrators can specify how to monitor addresses on separate NICs and trigger failover if any or all
monitored IP addresses have failed. In the event of an entire machine failure, the target has to assume the traffic from both
NICs and their assigned IP addresses, in addition to the traffic it is already processing.
NOTE: If a failover target is monitoring a source for failure and a new NIC is added to the target server, you will need
to reinstall Storage Mirroring to properly setup the new NIC for failover placeholders. An uninstall is not
necessary; you can reinstall by choosing the Repair or Upgrade option during the installation. For detailed
information on repairing or upgrading Storage Mirroring, see the Storage Mirroring Getting Started guide.
WARNING: With multiple source NICs or IP addresses you must carefully configure your monitoring and failover settings
to avoid causing IP address conflicts or compromising data integrity. To eliminate any potential for data integrity
problems or IP address conflicts, it is suggested that you monitor all IP addresses on the source machine, and
trigger failover when all IP addresses fail, when it is possible. For more information, see
Failover Options on
page 11-7 for information on Failover Trigger and Failover Execution .
Source
Target
One NIC with one or
more IP addresses
One NIC with one or
more IP addresses
Source
Target
One NIC with one or
more IP addresses
Multiple NICs with
more IP addresses
one or