Avago Technologies MegaRAID Fast Path Software - Manual (Page 493)

LSI Corporation Confidential | July 2011 Page 493
MegaRAID SAS Software User Guide Appendix C: Glossary
 Unconfigured Bad – A drive on which the firmware detects an unrecoverable error;
the drive was Unconfigured Good or the drive could not be initialized.
 Missing – A drive that was Online, but which has been removed from its location.
 Offline – A drive that is part of a virtual drive but which has invalid data as far as the
RAID configuration is concerned.
 None – A drive with an unsupported flag set. An Unconfigured Good or Offline
drive that has completed the prepare for removal operation.
drive subsystem A collection of drives and the hardware that controls them and connects them to one
or more controllers. The hardware can include an intelligent controller, or the drives can
attach directly to a system I/O bus controller.
drive type A drive property indicating the characteristics of the drive.
EKM External Key Management
fast initialization A mode of initialization that quickly writes zeroes to the first and last sectors of the
virtual drive. This allows you to immediately start writing data to the virtual drive while
the initialization is running in the background.
fault tolerance The capability of the drive subsystem to undergo a single drive failure per drive group
without compromising data integrity and processing capability. LSI SAS RAID
controllers provides fault tolerance through redundant drive groups in RAID levels 1, 5,
6, 10, 50, and 60. They also support hot spare drives and the auto-rebuild feature.
firmware Software stored in read-only memory (ROM) or programmable ROM (PROM). Firmware
is often responsible for the behavior of a system when it is first turned on. A typical
example would be a monitor program in a system that loads the full operating system
from drive or from a network and then passes control to the operating system.
foreign configuration A RAID configuration that already exists on a replacement set of drives that you install
in a computer system. MegaRAID Storage Manager software allows you to import the
existing configuration to the RAID controller, or you can clear the configuration so you
can create a new one.
formatting The process of writing a specific value to all data fields on a drive, to map out
unreadable or bad sectors. Because most drives are formatted when manufactured,
formatting is usually done only if a drive generates many media errors.
hole In MegaRAID Storage Manager, a hole is a block of empty space in a drive group that
can be used to define a virtual drive.
host interface A controller property indicating the type of interface used by the computer host
system: for example, PCIX.
host port count A controller property indicating the number of host data ports currently in use.
host system Any computer system on which the controller is installed. Mainframes, workstations,
and standalone desktop systems can all be considered host systems.
hot spare A standby drive that can automatically replace a failed drive in a virtual drive and
prevent data from being lost. A hot spare can be dedicated to a single redundant drive
group or it can be part of the global hot spare pool for all drive groups controlled by the
controller.
When a drive fails, MegaRAID Storage Manager software automatically uses a hot spare
to replace it and then rebuilds the data from the failed drive to the hot spare. Hot
spares can be used in RAID 1, 5, 6, 10, 50, and 60 storage configurations.