Avago Technologies 3ware SAS 9750-16i4e - Manual (Page 308)

Appendix A. Glossary
296 3ware SATA+SAS RAID Controller Card Software User Guide, Version 10.2
• Drive Number . The SCSI number, or channel number, of a particular
drive.
• ECC. Error correction code. ECC Errors are grown defects that have
occurred on a drive since it was last read.
• 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.
Specified by the
Ignore ECC (Continue on Source Error When
Rebuilding) unit policy.
• Enclosure. An enclosure houses drives and a backplane. The backplane
may have an expander.
• Expander. Expanders are simple switches in enclosures that provide
connectivity between the 3ware 9750 RAID controller and the other
devices in the SAS domain. Expanders allow one phy to connect to
multiple drives.
• 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
to another controller. Compare to Delete, which erases all unit
configuration information from the drive.
• Exportable unit or drive . In 3BM (BIOS), exportable units and drives
are those that will be available to the operating system when you boot
your computer.
• Fault tolerant . A RAID unit which provides the ability to recover from a
failed drive, either because the data is duplicated (as when drives are
mirrored) or because of error checking (as in a RAID 5 unit).
• Firmware. Computer programming instructions that are stored in a read-
only memory on the controller rather than being implemented through
software.
• Grown defect. Defects that arise on a disk from daily use.
• Hot spare. A drive that is available, online, and designated as a spare.
When a drive fails in a redundant unit, causing the unit to become
degraded, a hot spare can replace the failed drive automatically and the
unit will be rebuilt.
• Hot swapping . The process of removing a disk drive from the system
while the power is on. Hot swapping can be used to remove units with
data on them, when they are installed in hot swap bays. Hot swapping can
also be used to remove and replaced failed drives when a hot swap bay is
used.
• Import a unit . Attach a set of disk drives with an existing configuration to
a controller and make the controller aware of the unit. Does not affect the
data on the drives.