Using companion servers in a high availability system

The Sybase high availability system includes two Adaptive Servers, each physically located on different machines, that are connected so that, if one of the servers is brought down, the other assumes its work load. Adaptive Server may be brought down for any number of reasons such as scheduled maintenance, system failure, or power outage. The act of the second server assuming another server's workload is called failover. The act of moving the workload back to the original server once it is up and running again is called failback. The two machines are configured for dual access (for example, dual-ported SCSI's), which make the disks visible and accessible to both machines. Clients connected to the Adaptive Server that failed are automatically switched to the second machine, re-establishing their network connections.For more information about using companion servers, see the High Availability documentation.

Creating a companion server

From HA Services folder, start the Companion Server Creation wizard.
Type the name of the remote server that you want to be the companion server.
Click Get Advisory Information to start the compatibility check.

Right click the server name to display the Properties dialog box. The General tab displays this information:

Type – Either the primary or companion server.
State – One of these modes: Single-Server, Normal-Companion, Failover, Suspended-Companion
ID – Server ID
Class Name – Name of the server class.

From the State tab you can alter the state of the server to Drop, Suspend, Resume, Failback.