3Ware 9550SXU-16ML User Guide - Page 242

Appendix A. Glossary „ Configuration. The RAID level set for a unit. „ Controller ID number. The unique SCSI number in the Windows environment, or the Channel number in the Linux environment, of a particular controller. Typically assigned by the operating system. „ Create an array. The process of selecting individual disk drives and selecting a RAID level. The array will appear to the operating system as a single unit. Overwrites any existing unit configuration data on the drives. „ DCB. Disk configuration block. This is 3ware proprietary RAID table information that is written to disk drives that are in a RAID unit, single disk, or spare. The DCB includes information on the unit type, unit members, RAID level, and other important RAID information. „ Delete an array. Deleting an array (or unit) is the process of returning the drives in a unit to individual drives. This erases the DCB information from the drives and deletes any data that was on them. When a unit is deleted from a controller, it is sometimes referred to as being "destroyed." If you want to remove a unit without deleting the data on it, do not delete it; instead use the Remove feature in 3DM, and then physically remove the drives. „ Destroying. Same as deleting a unit. „ Degraded unit. A redundant unit that contains a drive that has failed. „ Disk roaming. When moving a unit from one controller to another, refers to putting disks back in a different order than they initially occupied, without harm to the data. „ Distributed parity. Parity (error correction code) data is distributed across several drives in RAID 5 and RAID 50 configurations. Distributing parity data across drives provides both protection of data and good performance. „ Drive ID. A unique identifier for a specific drive in a system. Also called a port ID. „ Drive Number. The SCSI number, or channel number, of a particular drive. „ ECC. Error correction code. „ ECC Error policy. Determines whether an error detected during a rebuild stops the rebuild or whether the rebuild can continue in spite of the error. „ EMS (Enclosure Management Services). Chassis-monitoring functions for environmental, power, mechanical monitoring, and control using the I²C bus port. „ Export a unit. To remove the association of a unit with a controller. Does not affect the data on the drives. Used for array roaming, when you want to swap out a unit without powering down the system, and move the unit 232 3ware 9550SX Serial ATA RAID Controller User Guide