IBM SG24-4576-00 - Manual (Page 66)

The primary server sends the disk changes over the mirrored server link to
update the repaired server and to mirror the contents of the disk. Disk mirroring
occurs in the background during idle cycles.
Scenario 2. Hardware fails in the secondary server: The primary server notifies
the system administrator that the secondary server is down and that it is still the
primary server.
SFT III keeps track of any disk changes following the secondary server
′
s failure.
The system administrator repairs and brings up the secondary server.
The primary server sends the memory image and disk changes across the
mirrored server link to update the secondary server and to re-synchronize the
two servers.
Scenario 3. The Mirrored server link fails: The secondary server detects that
information is not coming across the MSL.
However, server state packets are still coming across the IPX internet link,
indicating that the primary server is still active.
The secondary server shuts down because the primary is still servicing the
clients. Server mirroring is no longer possible.
SFT III keeps track of any disk changes following the secondary server
′
s
shutdown.
The system administrator repairs the mirrored server link and brings up the
secondary server.
The primary server sends the memory image and disk changes across the
mirrored server link to update the secondary server and to re-synchronize the
two servers.
Scenario 4. A LAN adapter fails in the primary server: The operating system
detects a LAN adapter failure in the primary server.
The operating system determines the condition of the secondary server
′
s LAN
adapters. If the secondary server
′
s LAN adapters are more functional and the
server is still mirrored, the secondary server takes over servicing clients on the
network.
The system administrator is notified of the failure on the server
′
s console screen
and an entry is made in the log file.
SFT III keeps track of any disk changes following the failed server
′
s shutdown.
The failed server will restart automatically and become the secondary server.
The active server sends the memory image and disk changes across the
mirrored server link to update the failed server and to re-synchronize the two
servers.
Chapter 1. IBM PC Server Technologies
51