Instruction manual

170
Cybernetics UM-MV-86-B1-0801
Optical Disc – An optical disc is an electronic data storage medium that can be written to
and read using a low-powered laser beam (e.g., CD-R/W, Blu-ray, ProData).
Optical Disc Drive – For the miSAN-V-Series, a SCSI drive that records data on an opti-
cal disc.
Physical Device – A physical tape drive or physical tape library. This is the miSAN-V-
Series
“back-end” as seen by the miSAN-V-Series. These devices are installed (internal),
attached (SCSI) or connected (iSCSI) to the miSAN-V-Series and are used for offloading
disk to tapes.
Physical Stacker – A physical tape library (these terms are used interchangeably). If the
miSAN-V-Series is not configured with optional Tape Library Control support, an external
tape library will appear to the miSAN-V-Series as a standalone tape drive. With optional
Tape Library Control support, the miSAN-V-Series can use an external tape library drive
and its slotted tapes.
Physical Tape – A data tape cartridge.
Physical Tape Drive – An installed (internal), attached (SCSI) or connected (iSCSI) tape
drive.
Physical Tape Library – An attached (SCSI) or connected (iSCSI) tape library. If the
miSAN-V-Series is not configured with optional Tape Library Control support, an external
tape library will appear to the miSAN-V-Series as a standalone tape drive. With optional
Tape Library Control support, the miSAN-V-Series can use an external tape library drive
and its slotted tapes.
RAID – “Redundant Array of Independent Disks” (RAID) is a grouping of disk drives (an
array) combined in such a way as to provide fault tolerance and increased write/read per-
formance. Several disk grouping methods exist, called RAID levels, which are configured
by a disk array controller in the storage enclosure. Most storage enclosures implement
the RAID levels described below. Configuring the RAID storage enclosure for the appro-
priate use will make the most effective use of disk storage resources and provide the cor-
rect level of fault tolerance.
RAID 0 – This is the most basic implementation of the Striping technique. However,
because this type of array has no inherent fault tolerance (i.e., redundancy), RAID 0 is not
true RAID unless it is used in conjunction with other RAID levels (e.g., RAID 10 and RAID
50).
RAID 0 arrays can provide high write performance relative to true RAID levels because
there is none of the overhead associated with parity calculations or other data recovery
techniques. This same lack of provision for rebuilding lost data means RAID 0 arrays
should be restricted to storage of noncritical data and combined with a strict backup pro-
gram.
In a RAID 0 array, which requires a minimum of two disks to be installed, storage capacity
for each disk is determined by the smallest disk in the array. For example, an array with a
100, 250 and 150 Gigabyte drive will show a total storage capacity of 300 Gigabytes (100
Gigabytes ×
3).
RAID 0 is recommended for use with large, non-critical file applications, such as multime-
dia and scientific computing.