ExpressCluster X 3.1 for Linux Getting Started Guide - Nec

Failover mechanismFailover resourcesExpressCluster can fail over the following resources:Switchable partitionResources such as disk resource, mirror disk resource and hybrid disk resource.A disk partition to store the data that the application takes over.Floating IP AddressBy connecting an application using the floating IP address, a client does not have to beconscious about switching the servers due to failover processing.It is achieved by dynamic IP address allocation to the public LAN adapter and sending ARPpacket. Connection by floating IP address is possible from most of the network devices.Script (exec resource) In ExpressCluster, applications are started up from the scripts.The file failed over on the shared disk may not be complete as data even if it is properlyworking as a file system. Write the recovery processing specific to an application at the timeof failover in addition to the startup of an application in the scripts.Note:In a cluster system, failover is performed by restarting the application from aproperly working node. Therefore, what is saved in an application memory cannot befailed over.System configuration of the failover type clusterIn a failover-type cluster, a disk array device is shared between the servers in a cluster. When anerror occurs on a server, the standby server takes over the applications using the data on the shareddisk.Public LANInterconnectdedicatedLANExpressClusterOSOSDataSharedDiskFigure 2-4 System configurationSection I Introducing ExpressCluster37