Administrator Guide

Table 43. Glossary of ME4 Series terms (continued)
Term Definition
IOPS I/O operations per second.
IQN iSCSI Qualified Name.
iSCSI Internet SCSI.
iSNS Internet Storage Name Service.
JBOD “Just a bunch of disks.” See expansion enclosure.
LBA Logical block address. The address used for specifying the location of a block of data.
leftover The state of a disk that the system has excluded from a disk group because the timestamp in the
disk’s metadata is older than the timestamp of other disks in the disk group, or because the disk was
not detected during a rescan. A leftover disk cannot be used in another disk group until the disk’s
metadata is cleared. For information and cautions about doing so, see documentation topics about
clearing disk metadata.
LFF Large form factor.
linear The storage-class designation for logical components such as volumes that do not use paged-storage
technology to virtualize data storage. The linear method stores user data in sequential, fully allocated
physical blocks, using a fixed (static) mapping between the logical data presented to hosts and the
physical storage where it is stored.
linear disk group For linear storage, a group of disks that is configured to use a specific RAID level. The number
of disks that a linear disk group can contain is determined by its RAID level. Any supported RAID level
can be used. When a linear disk group is created, a linear pool with the same name is also created to
represent the volume-containment properties of the disk group. See also linear pool.
linear pool For linear storage, a container for volumes that is composed of one linear disk group.
LIP Loop Initialization Primitive. An FC primitive used to determine the loop ID for a controller. lock key A
system-generated value that manages the encryption and decryption of data on FDE-capable disks.
See also FDE, passphrase.
loop See FC-AL.
LUN Logical Unit Number. A number that identifies a mapped volume to a host system.
MAC address Media Access Control Address. A unique identifier assigned to network interfaces for communication
on a network.
Management Controller See MC.
map/mapping Settings that specify whether a volume is presented as a storage device to a host system, and how
the host system can access the volume. Mapping settings include an access type (read-write, read-
only, or no access), controller host ports through which initiators may access the volume, and a LUN
that identifies the volume to the host system. See also default mapping, explicit mapping, masking.
masking A volume-mapping setting that specifies no access to that volume by hosts. See also default mapping,
explicit mapping.
MC Management Controller. A processor (located in a controller module) that is responsible for human-
computer interfaces, such as the PowerVault Manager, and computer-computer interfaces, such as
SNMP, and interacts with the Storage Controller. See also EC, SC.
metadata Data in the first sectors of a disk that stores disk-, disk-group-, and volume-specific information
including disk group membership or spare identification, disk group ownership, volumes and snapshots
in the disk group, host mapping of volumes, and results of the last media scrub.
MIB Management Information Base. A database used for managing the entities in SNMP. midplane The
printed circuit board to which components connect in the middle of an enclosure. mount To enable
access to a volume from a host OS. See also host, map/mapping, volume.
midplane The printed circuit board to which components connect in the middle of an enclosure.
mount To enable access to a volume from a host OS. See also host, map/mapping, volume.
Glossary of terms 175