What goes up must come down, but if your servers go down too often, your time as an employee may be up.
All servers fail from time to time, even when outfitted with high-availability hardware: error-correcting memory, multiple CPUs, RAID and redundant power supplies. Clustering software can help PC servers achieve levels of uptime and availability approaching that of minicomputers or mainframes by distributing server workload and replicating data across multiple shared hard disks or servers.
Clustering software typically works through network adapters that sense the health of each server, but sometimes the software requires the presence of special hardware. When failure occurs, the clustering software identifies the failed unit and routes the workload to other machines. Ideally, users see no interruption of service.
To determine which clustering software adds the most reliability to an NT server environment, we tested products from five vendors. Vinca Corp.’s Co-StandbyServer 4.1 for NT was clearly the best clustering software for making NT Server a reliable and highly available platform. Co-StandbyServer gave us the closest to 24-by-7 uninterrupted operation of our PC servers and was easy to administer.