Storage Clusters
Each controller frame consists of two redundant controller halves called storage clusters. Each
storage cluster contains all physical and logical elements (for example, power supplies, channel
adapters, disk adapters, cache, control storage) needed to sustain processing within the subsystem.
Both storage clusters should be connected to each host using an alternate path scheme, so that if
one storage cluster fails, the other storage cluster can continue processing for the entire subsystem.
The front-end and back-end directors are split between clusters to provide full backup. Each storage
cluster also contains a separate, duplicate copy of cache and shared memory contents. In addition to
the high-level redundancy that this type of storage clustering provides, many of the individual
components within each storage cluster contain redundant circuits, paths, and/or processors to
allow the storage cluster to remain operational even with multiple component failures. Each storage
cluster is powered by its own set of power supplies, which can provide power for the entire storage
subsystem in the unlikely event of power supply failure. Because of this redundancy, the ST9985V
can sustain the loss of multiple power supplies and still continue operation.
Note:
The redundancy and backup features of the ST9985V eliminate all active single points of
failure, no matter how unlikely, to provide an additional level of reliability and data availability.
Just the Facts
October 2007
36
Sun Confidential – For Internal Use and Authorized Partner Use Only
