Rebuild area Reclaimable (or reclaimed) capacity Redundant storage area network Relationship Reliability, availability, and serviceability Remote fabric Remote Support Server and Client SAN Volume Controller The IBM SAN Volume Controller is an appliance that is designed for attachment to various  host computer systems. The SAN Volume Controller performs block-level virtualization of disk  storage. IBM Spectrum Virtualize is a software engine of SAN Volume Controller (and  Storwize family) that performs block-level virtualization of disk storage. Remote Support Client is a software toolkit that resides in IBM Storwize V5000 and opens a  secured tunnel to the Remote Support Server. Remote Support Server resides in the IBM  network and collects key health check and troubleshooting informations required by IBM  support personnel. The remote fabric is composed of SAN components (switches, cables, and so on) that  connect the components (nodes, hosts, and switches) of the remote cluster together.  Significant distances can exist between the components in the local cluster and those  components in the remote cluster. Reliability is the degree to which the hardware remains free of faults. Availability is the ability  of the system to continue operating despite predicted or experienced faults. Serviceability is  how efficiently and nondisruptively broken hardware can be fixed. Reliability, availability, and serviceability (RAS) are a combination of design methodologies,  system policies, and intrinsic capabilities that, when taken together, balance improved  hardware availability with the costs that are required to achieve it.  In Metro Mirror or Global Mirror, the association between a master volume and an auxiliary  volume. These volumes also have the attributes of a primary or secondary volume. See also  “Auxiliary volume” on page 81 6, “Management node” on  page 827, primary volume,  secondary volume. A redundant SAN is a SAN configuration in which there is no single point of failure (SPoF);  therefore, data traffic continues no matter what component fails. Connectivity between the  devices within the SAN is maintained (although possibly with degraded performance) when  an error occurs. A redundant SAN design is normally achieved by splitting the SAN into two  independent counterpart SANs (two SAN fabrics), so that if one path of the counterpart SAN  is destroyed, the other counterpart SAN path keeps functioning. Reclaimable Data is the capacity that is no longer needed. Reclaimable capacity is created  when data is overwritten and the new data is stored in a new location, when data is marked as  unneeded by a host using the SCSI unmap command, or when a volume is deleted. Reserved capacity that is distributed across all drives in a redundant array of drives. If a drive  in the array fails, the lost array data is systematically restored into the reserved capacity,  returning redundancy to the array. The duration of the restoration process is minimized  because all drive members simultaneously participate in restoring the data. See also  “Distributed RAID or DRAID” on page 821. Appendix B. Terminology  831