Sybase’s failover and the high availability system enable users to access data while the server to which they were originally connected is down. However, neither of these systems prevent disk failures. To make sure you do not lose any data because of a disk failure, you should use Sybase’s failover in conjunction with a data protection mechanism, such as disk mirroring or RAID.
Sybase disk mirroring is not supported in an Adaptive Server companion cluster, and is disabled when you issue sp_companion to configure the Adaptive Servers as companions. Use a third-party vendor mirroring system to protect your disk devices.
