Terminology definitions
| Term | Definition |
|---|---|
| Spindle | A Spindle is a physical hard disk. |
| Disk Group | A Disk Group is a set of physical hard disks
(or spindles) that are grouped into a disk array. See section RAID levels overview, for details about disk arrays. |
| Disk array | Same as Disk Group. |
| RAID | A RAID is a logical device that uses a Disk Group, applying specific rules to form one storage unit. |
| LUN | A LUN is a logical device that is part of a disk array, or is an entire disk array. A LUN is exported from SAN and presented to an OS as one single logical disk device. Multiple LUNs can be exported to an OS and presented as different devices that share physical RAID array. |
| SCSI disk | A SCSI disk is a fast physical hard disk that is used for performance. The main beneficial characteristic is RPM (rotations per minute). |
| SATA disk | A SATA disk is normally slower than a SCSI disk but can have the advantage of having greater capacity than a SCSI disk. SATA disks can be used to store files where IO performance is not the major factor. |
| SAS | Serial Attached SCSI. A computer bus that is used to move data to and from storage devices. |
Note: All external file systems must reside on SAN.