To configure the Cluster Edition for a round-robin method, use:
sp_addserver 'SYB_BACKUP', NULL, '$ROUNDROBIN'
Once you configure the Cluster Edition to use the round-robin method, the Cluster Edition selects a Backup Server for a dump or load command according to which Backup Server that is performing the least amount of work.
For example, if a user connects to instance Inst1 from isql and issues a dump command from this session, instance Inst1 checks the SYB_BACKUP entry in sysservers, and finds that it points to keyword $ROUNDROBIN. If Inst1_BS is busy performing another task, the Cluster Edition moves to the next Backup Server, Inst2_BS. If Inst2_BS is available, with no jobs running on it, this Backup Server performs the dump, and its index is incremented to indicate that it is busy and unavailable for work. However, if Inst2_BS is busy, the Cluster Edition moves to the next Backup Server, and so on until it finds a free Backup Server.
If all Backup Servers are busy, the Cluster Edition routes the dump or load request to the Backup server with the least number of running parallel requests. The Cluster Edition automatically restarts any Backup Servers that are not running.
