HP Storage Mirroring Software - Manual (Page 158)

Workload protection Page 157 of 677
l
Revert to Last Good Snapshot if Target Data is Bad—If the target data is
in a bad Storage Mirroring Recover state, Storage Mirroring Recover will
automatically revert to the last good Storage Mirroring Recover snapshot
before failover begins. You will lose any data between the last good
snapshot and the failure. If the target data is in a good state, Storage
Mirroring Recover will not revert the target data. Instead, Storage Mirroring
Recover will apply the data in the target queue and then failover. Depending
on the amount of data in queue, the amount of time to apply all of the data
could be lengthy.
15. Highlight the source name and specify the Items to Failover, which identifies
which source components you want to failover to the target.
l
IP Addresses—If you want to failover the IP addresses on the source,
enable this option and then specify the addresses that you want to failover.
l
Monitored—Only the IP address(es) that are selected for monitoring will be
failed over.
l
All—All of the IP address(es) will be failed over.
Note: If you are monitoring multiple IP addresses, IP address conflicts may
occur during failover when the number of IP addresses that trigger
failover is less than the number of IP addresses that are assumed by
the target during failover. For example, if a source has four IP
addresses (three public and one private), and two of the three public
addresses are monitored, but all three public addresses are
configured to failover, a conflict could occur. If the source fails, there is
no conflict because all of the IP addresses have failed and no longer
exist. But if the failure only occurs on one of the monitored addresses,
the other two IP addresses are still affected. If all of the addresses are
failed over, these addresses then exist on both the source and the
target. Therefore, when a source machine has fewer IP addresses that
trigger failover than IP addresses that will be failed over, there is a risk
of an IP address conflict.
If your network environment is a WAN configuration, do not failover
your IP addresses unless you have a VPN infrastructure so that the
source and target can be on the same subnet, in which case IP
address failover will work the same as a LAN configuration. If you do
not have a VPN, you can automatically reconfigure the routers via a
failover script (by moving the source's subnet from the source's
physical network to the target's physical network). There are a number
of issues to consider when designing a solution that requires router
configuration to achieve IP address failover. Since the route to the