98
C
HAPTER
4: S
ERVER
F
AILOVER
C
ONFIGURATION
■
if it is trying to re-establish a connection to the Active Server, it will
short-out the failover retry and timeout mechanism, make itself the
Active Server and let the client connect.
■
if it still has a connection to the Active Server, it refuses to let the client
connect.
How the Failover
System Works
The server-to-server connection mechanism is a continuous connection
and, due to its continuous nature, the Dormant server knows the
connection is lost as soon as it happens. When the connection is lost, the
Dormant server tries to re-establish a connection using the same
mechanism used during server startup, as described in
“Setting the Retry
and Timeout for EMS Startup”
.
However, if the Dormant server receives a client connection request
while retrying its connection, the Dormant server assumes that the
Active server has definitely failed and failover occurs immediately. See
“Server Failover Mechanism”
for details on the transition from Dormant
to Active server.
Server Failover Mechanism
Once the Dormant server realizes that the Active server is no longer
available, it logs this message to its command window (and the audit
log):
**** Server Failover: failover occurred at
<date/time> ****
The server stops trying to open a connection to what was the Active
server, and assumes the Active server role itself.
“Active Server
Behaviors”
defines how the various EMS services behave.
If trap forwarding has been set up, the server will send a Major
severity trap stating that server failover has occurred by reporting:
Server Failover: failover occurred
. The date and time of the
event is implied based on when the trap is received.
Summary of Contents for 3CR15600 - Enterprise Management Suite
Page 12: ...12 ...
Page 16: ...16 ABOUT THIS GUIDE ...
Page 40: ...40 CHAPTER 1 PRODUCT OVERVIEW ...
Page 54: ...54 CHAPTER 2 PRE INSTALLATION ...
Page 100: ...100 CHAPTER 4 SERVER FAILOVER CONFIGURATION ...
Page 123: ...Schedulable GUI Based Device Discovery 123 Figure 32 Session Preferences Discovery Tab Boxes ...
Page 132: ...132 CHAPTER 6 GUI CLIENT CONFIGURATION ...
Page 166: ...166 CHAPTER 9 NETWORK MANAGEMENT PLATFORM INTEGRATION CONFIGURATION ...
Page 206: ...206 CHAPTER 10 OPERATIONS ...
Page 212: ...212 APPENDIX A COMMAND LINE INTERFACE REFERENCE ...
Page 218: ...218 INDEX ...