A High Availability (HA) cluster is a set of servers (nodes) managed by clusterware to work together for minimizing application downtime as much as possible. Clusterware enables servers to communicate with each other, so that they appear to function
Virtual Tape Library consists of several components. LLD - A low level driver implemented as a kernel module - mhvtl Target devices - Daemons vtltape(1) and vtllibrary(1) which implement SCSI target device(s) in user-space Utility commands mktape(1)