HP Storage Mirroring V5.1 Software - Manual (Page 129)

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Failover manual intervention
If Manual Intervention is enabled, the Failover Control Center will prompt you when a failure occurs.
Click Cancel to abort the failover process. If necessary, you can initiate failover later from the Failover
Control Center. Click OK to proceed with failover.
You will be prompted to specify what data you want to use on the target.
Select an option based on the table below. You may want to check the amount of data in queue on
the target by reviewing the Storage Mirroring Performance Monitor or DTStat.
NOTE: If the Failover Control Center is not running at the time the failure occurs, the manual
intervention dialog box will appear the next time the Failover Control Center is started.
When a failure occurs, an alert is forwarded to the Windows Event Viewer. You can then
start the Failover Control Center and respond to the manual intervention prompt.
If SNMP is installed and configured, an SNMP trap is also generated. When using a
third-party SNMP manager, an e-mail or page can be generated to notify you of the
failure.
Target Data
State at
Failover
Description Advantages Disadvantages
Apply Data in
Target
Queues Then
Failover
All of the data in the target queue
will be applied before failover begins.
All of the data that
the target has
received will be
applied before
failover begins.
Depending on the
amount of data in
queue, the amount
of time to apply all
of the data could
be lengthy.
Discard Data
in Target
Queues and
Failover
Immediately
All of the data in the target queue
will be discarded and failover will
begin immediately.
Failover will occur
immediately.
Any data in the
target queue will
be lost.
Revert to Last
Good
Snapshot if
Target Data is
Bad
If the target data is in a bad Storage
Mirroring state, Storage Mirroring
will automatically revert to the last
good Storage Mirroring snapshot
before failover begins. If the target
data is in a good state, Storage
Mirroring will not revert the target
data. Instead, Storage Mirroring will
apply the data in the target queue
and then failover.
Good data on the
target is
guaranteed to be
used.
If the target data
state is bad, you
will lose any data
between the last
good snapshot and
the failure.