The next two figures show a detailed view of a filled in Heartbeat Configuration form for the primary APM in the configuration, and a detailed view of a filled in Heartbeat Configuration form for the redundant APM. The two forms are filled out almost identically, but observe the following fields in the two forms to see how they differ:
The primary system is the system that runs under normal conditions. Ideally, this is always the case. The redundant system is the system that takes over if the primary system fails or the heartbeat signal is interrupted. The current system is the primary system when you are configuring the primary system. It is the redundant system when you are configuring the redundant system. The mated system is the redundant system when you are configuring the primary system. It is the primary system when you are configuring the remote system.Note: Most of the fields in the APM Heartbeat forms for the primary APM and for the redundant APM must be filled in identically. The two foregoing figures show which fields differ and how they differ when comparing the APM Heartbeat form for the primary APM to the APM Heartbeat form for the secondary APM.
Time in seconds before a missing heartbeat signal is recognized as a failure of the primary APM (default: 5 seconds). Time in seconds for a heartbeat signal to be sent and acknowledged (default: 1 second). Dead-Ping Time Out Time in seconds for an APM to consider a ping to have failed (default: 5 seconds). Configured State Drop-down menu to the APM you are currently configuring either the “PRIMARY” or the “REDUNDANT” APM in the configuration. Drop-down menu to select CRC (default - no authentication), MD5, or SHA1. Shared Secret Key A password common to the primary APM and the redundant APM. IP address assigned to the APM web service. The same IP address must be assigned for this field on the primary and on the redundant APM. Drop-down box to either “Enable” or “Disable” the heartbeat - redundancy - failover feature. This must be enabled, or you cannot edit any of the other fields under the “System” tab. A list of IP addresses to ping in order to detect when primary APM has lost connectivity to the network. Be sure to separate the IP addresses with commas and no spaces. It is recommended that this field includes the default gateway IP address and the router IP address. The aliases of the APMs you are configuring. There are two fields: one field is for the current system, and the other field is for the mated system.The current system is the primary system when you are configuring the primary system and it is the redundant system when you are configuring the redundant system.Note: Compare these fields in the two foregoing figures. The IP addresses of the APMs you are configuring. There are two fields: one field is for the current system, and the other field is for the mated systemThe current system is the primary system when you are configuring the primary system and it is the redundant system when you are configuring the redundant system.Note: Compare these fields in the two foregoing figures. Force Fail Over/
Force Fail Back If you are viewing the Heartbeat form for the primary APM, this button is labeled “Force Failover”. If you are viewing the Heartbeat form for the redundant APM, this button is labeled “Force Failback”.
Synchronization Speed The default is 700000 KB/second. This is the maximum speed allowed for this field.Note: The APM 2500 and the APM 5000 synchronize using network RAID and DRBD (Distributed Replicated Block Device). This enables replication of data from the primary system to the redundant system in real time. To Set Up a Fault Tolerant APM Configuration
1. Be sure both APM systems are upgraded with the same APM 1.4.0 GA release (refer tothe “AlterPath Manager Installation, Configuration, and User’s Guide”) .Caution: You can mix APM hardware platforms, but you must be sure the APM 5000 has APM 5000 firmware and the APM 2500 has APM 2500 firmware. Both APMs must have firmware of the same build number and date.
2. From the primary APM’s console, run the backup command on the primary APM system and back up the database:
a. Perform a “backup conf”.
example:
# backup conf root@192.168.48.100:backup.conf
b. Perform a “backup log”.
example:
# backup log root@192.168.48.100:backup.log
3. From the redundant APM’s console, run the restore command on the remote APM system and restore the database:
a. Perform a “restore conf”.
example:
# restore conf root@192.168.48.100:backup.conf
b. Perform a “restore log”.
example:
# restore log root@192.168.48.100:backup.log
4. Physically configure two APMs with Eth0 ports on a common LAN. The IP addresses of the APMs must be static(see the figure Connecting 2 APMs in a Redundant Configuration
5. Connect the Eth1 ports on both APMs with a Cat-5 Ethernet crossover cable. This is the heartbeat and network RAID signal cable.