53 HA CONFIGURATIONHA Overview The Switch 7758 supports high availability (HA) feature. This feature is to achieve ahigh availability of the system and to recover the system as soon as possible in theevent of failures so as to shorten the mean time between failures (MTBF) of thesystem.The functions of HA are mainly implemented by the application running on Fabricmodule. A Switch 7758 has two Fabrics which are working in the master-slavemode: one module works in master mode as the master module, the other worksin slave mode as a backup module. If the master-slave system detects a fault in themaster module, a hot master-slave switchover will be performed automatically.The slave module will try to connect and control the system bus while the originalmaster module will try to disconnect with the bus. Thus, the master-slaveswitchover of the active system is completed, and at the same time the originalmaster module is reset to function as the slave module. Therefore, even if themaster module fails, the slave module can also take its role to ensure that theSwitch 7758 runs normally.The Switch 7758 supports hot swap of Fabrics. The hot swap of master moduleswill cause switchover master/slave.The Switch 7758 supports manually switchover master/slave. You can change thecurrent module state manually by executing command.c CAUTION: The HA feature of the Switch 7758 can detect the software upgrade ofthe two Fabric with at least one Fabric being active. However, the Fabric and theI/O Module of the Ethernet switches must be identical in their software version,otherwise they cannot work normally. So that during the upgrade, you arerecommended to restart the whole switch after the Fabric executes the bootboot-loader command, to ensure the normal operating of the switch.The configuration file of the slave module is copied from the master module in realtime, which can ensure that the slave system continues to operate in the sameconfiguration as that of the original active system after the master-slaveswitchover. The Switch 7758 supports automatic synchronization of configurationfile. The active system stores its configuration file and backup the configurationfile to the slave system simultaneously when the master’s configuration file ismodified, so as to ensure the consistency of the configurations of the activesystem and slave system. And you can also use command to manually synchronizethe configuration file of the master and slave module.Besides, the system can monitor the power supply and the operating environmentof the system and give timely alarms to avoid the escalation of failures and ensuresafe operations of the system.
