HP Storage Mirroring Software - Manual (Page 142)

11 - 3
How Failover Works
1. The target machine monitors the source machine and waits for a failure.
2. A source failure is detected and the failover process begins. (For more information on failure detection, see How Failure
Detection Works on page 11-5.)
3. If specified, a pre-failover script executes on the target. This script is user-defined and optional. Scripts may be used to
stop services on the target that will not be needed or may be in conflict after the target stands in for the failed source.
Scripts can also send network messages notifying administrators that failover is about to occur.
4. Depending on the source and target machine operating system, one of the following failover events will occur:
! Windows 200x —The failed source’s machine name, IP address, and subnet mask are added to the target’s identity.
! Windows NT 4.0 —The failed source’s machine name, IP address, and subnet mask are added to the target’s identity.
Although there is an option to replace the target’s identity with that of the source, the add option is recommended
to ensure that there are no IP address conflicts upon failback.
NOTE: Until the failover process has completed executing, user and application requests destined for the source
machine will not be delivered.
User and application requests are sent to
Source Name: Marketing
IP Address: 125.7.82.43
Target Name: Backup
IP Address: 125.7.82.67
Monitor Requests
and Replies
the source by locating the IP address
Failed Source
Target Name: Backup
IP Address: 125.7.82.67
Failover Script
User and application momentarily wait
while failover occurs
Failed Source
IP Address:
Target Name:
Backup and Marketing
125.7.82.67 and 125.7.82.43
User and application requests are sent to the target by
locating the IP address