Glossary

A

access mode: One of the modes in which a logical unit (LU) in a disk controller system can operate. The three access modes are image mode, managed space mode, and unconfigured mode. See also image mode, managed mode, unconfigured mode.
Address Resolution Protocol (ARP): A protocol that dynamically maps an IP address to a network adapter address in a local area network.
Advanced Settings Utility (ASU): A Lenovo utility that is used to modify firmware settings through command-line instructions.
agent code: An open-systems standard that interprets Common Information Model (CIM) requests and responses as they are transferred between the client application and the device.
alert: An informational event that requires user action. Also referred to as a notification.
ARP: See Address Resolution Protocol.
array: An ordered collection, or group, of physical devices (disk drive modules) that are used to define logical volumes or devices. An array is a group of drives designated to be managed with a Redundant Array of Independent Disks (RAID). See also Redundant Array of Independent Disks.
association: A class that contains two references that define a relationship between two referenced objects.
ASU: See Advanced Settings Utility (ASU).
asymmetric virtualization: A virtualization technique in which the virtualization engine is outside the data path and performs a metadata-style service. The metadata server contains all the mapping and locking tables while the storage devices contain only data. See also symmetric virtualization.
asynchronous replication: In replication, the process of copying data from a source table to a target table outside the scope of the original transaction that updated the source table. See also synchronous replication.
audit log: An unalterable log file that records all successful configuration commands and the identity of who issued them.
automatic support notification: A notification that is generated and automatically sent to Lenovo Support when an error occurs.
auxiliary volume: The volume that contains a mirror of the data on the master volume. See also master volume, relationship.
availability: The delivery of reliable service during scheduled periods.

B

backup

A copy of a data set or object to be used in case of accidental loss.

bandwidth

The amount of information that a system can transfer in a given time.

bay

A physical space into which a device can be physically mounted and connected to power and data. For example, a power supply or a disk drive might be inserted into a bay. See also CMM bay, drive bay, fan bay, fan logic bay, I/O bay, node bay, power-supply bay, and storage bay.

bitmap

A coded representation in which each bit, or group of bits, represents or corresponds to an item; for example, a configuration of bits in main storage in which each bit indicates whether a peripheral device or a storage block is available or in which each group of bits corresponds to one pixel of a display image.

block

A unit of data storage on a device.
To suspend a program process.

BoMC

See Bootable Media Creator (BoMC).

Boolean

Characteristic of an expression or variable that can only have a value of true or false.

Bootable Media Creator (BoMC)

A Lenovo utility that is used to create a single bootable image on supported media (CD, DVD, ISO image, USB flash drive, or a set of PXE files) that bundles multiple tools and updates from UpdateXpress System Packs, which contain Windows and Linux firmware and device-driver updates.

C

CA: See Certificate Authority (CA).
cache: Memory used to improve access times to instructions, data, or both. Data that resides in cache memory is normally a copy of data that resides elsewhere in slower, less expensive storage, such as on a disk or on another network node.
caching I/O group: The I/O group in the system that performs the cache function for a volume.
call home: A communication link established between a product and a service provider. The product can use this link to place a call to Lenovo or to another service provider when it requires service. With access to the machine, service personnel can perform service tasks, such as viewing error and problem logs or initiating trace and dump retrievals.
centralized management: An IBM Flex System Manager management domain configuration in which the Flex System Manager management software controls a single user repository for user accounts for multiple chassis and nodes. Under this configuration, all administrative users are authenticated against an LDAP directory that is hosted on the Flex System Manager management node. Contrast with decentralized management.
Certificate Authority (CA): A trusted central administrative entity that can issue digital certificates to users and servers. It can be a public commercial entity or a private entity that an organization operates for internal purposes.
chain: A set of enclosures that are attached to provide redundant access to the drives inside the enclosures. Each control enclosure can have one or more chains.
Challenge Handshake Authentication Protocol (CHAP): An authentication protocol that protects against eavesdropping by encrypting the user name and password.
CHAP: See Challenge Handshake Authentication Protocol.
CHAP secret: In the Challenge-Handshake Authentication Protocol (CHAP), a secret passphrase that is used to authenticate a storage system to iSCSI-attached hosts.
chassis: The metal frame in which various electronic components are mounted.
Chassis Management Module (CMM): A device that is used to configure and manage components in a Lenovo Flex System chassis.
Chassis Manager: An element in the IBM Flex System Manager web interface that shows high-level inventory and aggregated status information about managed resources within a chassis. The Chassis Manager also enables the user to configure certain resource actions and settings.
chipkill: An advanced error checking and correcting (ECC) memory technology that protects memory systems from any single memory chip failure and multi-bit errors from any portion of a single memory chip.
CIFS: See Common Internet File System.
CIM: See Common Information Model.
CIM object manager (CIMOM): The common conceptual framework for data management that receives, validates, and authenticates the CIM requests from the client application. It then directs the requests to the appropriate component or service provider.
CIMOM: See CIM object manager.
class: The definition of an object within a specific hierarchy. A class can have properties and methods and can serve as the target of an association.
client: A software program or computer that requests services from a server. See also host.
client application: A storage management program that initiates Common Information Model (CIM) requests to the CIM agent for the device.
clone: A copy of a volume on a server at a particular point in time. The contents of the copy can be customized while the contents of the original volume are preserved.
cluster: See clustered system.
clustered system: A collection of nodes that are placed in pairs (I/O groups) for redundancy, which provide a single management interface. See also system.
CMM: See Chassis Management Module (CMM).
CMM bay: The dedicated bay in a Lenovo Flex System chassis in which a Chassis Management Module is installed.
command-line interface: A type of computer interface in which the input command is a string of text characters.
Common Information Model (CIM): An implementation-neutral, object-oriented schema for describing network management information. The Distributed Management Task Force (DMTF) develops and maintains CIM specifications.
Common Internet File System (CIFS): A protocol that enables collaboration on the Internet by defining a remote file-access protocol that is compatible with the way applications already share data on local disks and network file servers.
compression: A function that removes repetitive characters, spaces, strings of characters, or binary data from the data being processed and replaces the repetitive characters with control characters. Compression reduces the amount of storage space that is required for the data.
compute node: An independent server that is supported in a Lenovo Flex System chassis and contains one or more microprocessors, memory, storage, and network controllers. It runs its own operating system and applications.
configuration node: A node that acts as the focal point for configuration commands and manages the data that describes the clustered-system configuration.
consistency group: A group of copy relationships between virtual volumes or data sets that are maintained with the same time reference so that all copies are consistent in time.
container: A software object that holds or organizes other software objects or entities.
contingency capacity: For thin-provisioned volumes that are configured to automatically expand, the unused real capacity that is maintained. For thin-provisioned volumes that are not configured to automatically expand, the difference between the used capacity and the new real capacity.
control enclosure: A hardware unit that includes the enclosure chassis, node canisters, drives, and system function.
counterpart SAN: A non-redundant portion of a redundant storage area network (SAN). A counterpart SAN provides all the connectivity of the redundant SAN but without the redundancy. Each counterpart SAN provides an alternate path for each SAN-attached device. See also redundant SAN.
cross-volume consistency: A consistency group property that guarantees consistency between volumes when an application issues dependent write operations that span multiple volumes.
CRU: See customer replaceable unit (CRU).
customer replaceable unit (CRU): A field replaceable unit that a customer can replace.

D

data center: A centralized repository of data and information relating to a particular field of knowledge.
data migration: The movement of data from one physical location to another without disruption of application I/O operations.
decentralized management: An IBM Flex System Manager management domain configuration in which the Chassis Management Module uses its own user registry, not the Flex System Manager registry, or uses an external user repository such as an external LDAP server. Contrast with centralized management.
defunct: Pertaining to a physical drive that has lost communication with its controller.
dense wavelength division multiplexing (DWDM): A technology that places many optical signals onto one single-mode fiber using slightly different optical frequencies. DWDM enables many data streams to be transferred in parallel.
dependent write operation: A write operation that must be applied in the correct order to maintain cross-volume consistency.
destage: To move data from cache to a nonvolatile storage medium.
device: A piece of equipment such as a workstation, printer, disk drive, tape unit, or remote system.
device provider: A device-specific handler that serves as a plug-in for the Common Information Model (CIM); that is, the CIM Object Manager (CIMOM) uses the handler to interface with the device.
directed maintenance procedure: See fix procedure.
discovery: The automatic detection of a network topology change, for example, new and deleted nodes or links.
disk zone: A zone that is defined in the storage area network (SAN) fabric in which the systems can detect and address the logical units (LUs) that the storage systems present.
Distributed Management Task Force (DMTF): An alliance of computer vendors that was convened to define streamlined management of the diverse operating systems commonly found in an enterprise.
DMTF: See Distributed Management Task Force.
DNS: See domain name server.
domain name server (DNS): A server program that supplies name-to-address conversion by mapping domain names to IP addresses.
DRAM: See dynamic random access memory.
drive: A data storage device. A drive can be either a magnetic disk drive or a solid-state drive (SSD).
drive bay: A dedicated bay in a Lenovo Flex System chassis in which a disk drive or solid-state drive can be installed.
DSA: See Dynamic System Analysis (DSA).
DS Storage Manager: See graphical user interface.
DWDM: See dense wavelength division multiplexing.
dynamic random access memory (DRAM): Storage in which the cells require repetitive application of control signals to retain stored data.
Dynamic System Analysis (DSA): A system information collection, analysis, and diagnostics tool that is used by Lenovo service and support personnel to aid in the diagnosis of system problems.

E

EC: See engineering change.
EIA: See Electronic Industries Alliance.
Electronic Industries Alliance (EIA): An organization of electronics manufacturers that advances the technological growth of the industry, represents the views of its members, and develops industry standards.
engineering change (EC): An update to a machine, part, or program. Each EC for a given unit is assigned a unique number referred to as an EC level or EC number.
environment service module canister: See expansion canister.
EUI: See extended unique identifier.
event: A user activity or system activity that is logged with an applicable message.
exclude: To prevent the use of a managed disk (MDisk) by a clustered system because of certain error conditions.
expansion canister: A hardware unit that includes the serial-attached SCSI (SAS) hardware that enables the node hardware to use the drives of the expansion enclosure.
expansion enclosure: A hardware unit that includes enclosure chassis, expansion canisters, drives, and function that allows extra drives to be connected.
extended unique identifier (EUI): A unique iSCSI name that identifies an iSCSI target adapter or an iSCSI initiator adapter as defined by the iSCSI standard (RFC 3722).
extent: A unit of data that manages the mapping of data between managed disks (MDisks) and volumes.
external storage: Managed disks (MDisks) that are SCSI logical units presented by storage systems that are attached to and managed by the clustered system.

F

F_port: See fabric port.
fabric port (F_port): An access point that is part of a Fibre Channel fabric. An F_port on a Fibre Channel fabric connects to a node's node port (N_port).
failover: An automatic operation that switches to a redundant or standby system in the event of a software, hardware, or network interruption.
fan bay: A dedicated bay in a Lenovo Flex System chassis in which a fan module can be installed.
fan distribution card: A component in a Lenovo Flex System chassis that passes power and signals from the midplane to the fan modules and the fan logic modules.
fan logic bay: A dedicated bay in a Lenovo Flex System chassis in which a fan logic module is installed.
fan logic module: A hot-swap device in a Lenovo Flex System chassis that enables the Chassis Management Module to monitor the fan modules in the chassis.
fan module: A hot-swap device in a Lenovo Flex System chassis that contains a cooling fan.
FC: See Fibre Channel.
FCIP: See Fibre Channel over IP.
Features on Demand: A software-delivery mechanism in which optional software is preinstalled in a device and activated through a key that is purchased from Lenovo.
Fibre Channel (FC): A technology for transmitting data between computer devices. It is especially suited for attaching computer servers to shared storage devices and for interconnecting storage controllers and drives. See also zoning.
Fibre Channel extender: A device used to extend a Fibre Channel link over a greater distance than is supported by the standard, usually a number of miles or kilometers. Devices must be deployed in pairs at each end of a link.
Fibre Channel over IP (FCIP): A network storage technology that combines the features of the Fibre Channel Protocol and the Internet Protocol (IP) to connect distributed SANs over large distances.
Fibre Channel port fan-in: The number of hosts that can detect any one port.
field replaceable unit (FRU): An assembly or part that must be replaced by a trained service technician, unless it is classified as a customer replaceable unit.
File Transfer Protocol (FTP): In TCP/IP, an application layer protocol that uses TCP and Telnet services to transfer bulk-data files between machines or hosts.
fix procedure: A maintenance procedure that runs within the product application and provides step-by-step guidance to resolve an error condition.
FlashCopy mapping: A continuous space on a direct-access storage volume, which is occupied by or reserved for a particular data set, data space, or file.
FlashCopy relationship: See FlashCopy mapping.
FlashCopy service: A copy service that duplicates the contents of a source volume on a target volume. In the process, the original contents of the target volume are lost. See also point-in-time copy.
flexible system-management processor: The system-management processor in a Power Systems node.
flush-through mode: See write-through mode.
front LED card: A component in a Lenovo Flex System chassis that controls the LEDs on the front information panel.
FRU: See field replaceable unit (FRU).
FTP: See File Transfer Protocol.
FTP server: A software or hardware server that responds to File Transfer Protocol.

G

gateway: An entity that operates above the link layer and converts, when required, the interface and protocol used by one network into those used by another distinct network.
GB: See gigabyte.
GBIC: See gigabit interface converter.
gigabit interface converter (GBIC): An encoding/decoding device that is a class-1 laser component assembly with transmitting and receiving receptacles that connect to fiber-optic cables. GBICs perform a serial optical-to-electrical and electrical-to-optical conversion of the signal. The GBICs in the switch can be hot-swapped.
gigabyte (GB): For processor storage, real and virtual storage, and channel volume, 10 to the power of nine or 1,073,741,824 bytes. For disk storage capacity and communications volume, 1,000,000,000 bytes.
Global Mirror: An asynchronous copy service that enables host data on a volume to be mirrored over long distances to a volume in a remote location.
grain: In a FlashCopy bitmap, the unit of data represented by a single bit.
graphical user interface (GUI): A computer interface that presents a visual metaphor of a real-world scene, often of a desktop, by combining high-resolution graphics, pointing devices, menu bars and other menus, overlapping windows, icons and the object-action relationship.
GUI: See graphical user interface.

H

hardcoded: Pertaining to software instructions that are statically encoded and not intended to be altered.
hard disk drive: See drive.
hard restart: A service reset that is performed through the Chassis Management Module web interface or command-line interface and resets the system-management processor in a compute node.
hard shutdown: A process in which a system powers off immediately without shutting down the operating system in an orderly way or allowing the user to save data. Contrast with soft shutdown.
hop: One segment of a transmission path between adjacent nodes in a routed network.
host: A computer that is connected to a network and that provides an access point to that network. The host can be a client, a server, or both a client and server simultaneously. See also client.
host group: See host.
host ID: A numeric identifier assigned to a group of host Fibre Channel ports for the purpose of logical unit number (LUN) mapping. For each host ID, there is a separate mapping of Small Computer System Interface (SCSI) IDs to volumes.
host interface card: An optional part of a node canister that provides the system with additional host and storage connectivity options.
host mapping: The process of controlling which hosts have access to specific volumes within a clustered system.
host zone: A zone that is defined in the storage area network (SAN) fabric in which the hosts can address the system.
hot-spare: Pertaining to redundant hardware (such as an adapter, a disk, a drive, or a server) that is installed and available in the event of a hardware failure.
hot swap: To replace a hardware component without turning off the system.
HTTPS: See Hypertext Transfer Protocol Secure.
hub: A point, or piece of hardware, that connects multiple devices in a network.
Hypertext Transfer Protocol Secure (HTTPS): An Internet protocol that is used by web servers and web browsers to transfer and display hypermedia documents securely across the Internet.

I

I2C

Inter-Integrated Circuit, a serial bus that attaches low-speed peripheral devices to the system board.

IBM Flex System Manager management node

An optional component in a Lenovo Flex System chassis that provides local or remote configuration and management support for multiple chassis and for the compute nodes and other devices in the chassis.

IBM Flex System Manager management software

The software stack that is preinstalled in an IBM Flex System Manager management node and provides a consistent interface for managing multiple Lenovo Flex System chassis and the compute nodes and other devices in the chassis.

IBM Systems Director

A platform-management foundation that streamlines management of physical and virtual systems across a heterogeneous environment.

ID

See identifier.

identifier (ID)

A sequence of bits or characters that identifies a user, program, device, or system to another user, program, device, or system.

idling

The status of a pair of volumes that have a defined copy relationship for which no copy activity has yet been started.

illegal configuration

A configuration that will not operate and will generate an error code to indicate the cause of the problem.

image mode

An access mode that establishes a one-to-one mapping of extents in the storage pool with the extents in the volume. See also access mode, managed mode, unconfigured mode.

image volume

A volume in which there is a direct block-for-block translation from the managed disk (MDisk) to the volume.

IML

See initial microcode load.

IMM2

See integrated management module II (IMM2).

initial microcode load (IML)

The loading of microcode from a storage medium into memory.

initiator

The system component that originates an I/O command over an I/O bus or network. I/O adapters and network interface cards are typical initiators. See also target.

input/output (I/O)

Pertaining to a device, process, channel, or communication path involved in data input, data output, or both.

input/output operations per second (IOPS)

A standard computing benchmark used to determine the best configuration settings for servers.

instance

In object-oriented programming, a region of storage that contains a value or group of values.
A specific occurrence of an object that belongs to a class. See also object.

integrated management module II (IMM2)

A service processor that combines systems-management functions, video controller, remote presence, and blue-screen capture features in a single chip.

integrity

In computer security, assurance that the information that arrives at a destination is the same as the information that was sent.

internal storage

Array managed disks (MDisks) and drives that are held in enclosures and in nodes that are part of the clustered system.

Internet Protocol (IP)

A protocol that routes data through a network or interconnected networks. This protocol acts as an intermediary between the higher protocol layers and the physical network.

Internet Storage Name Service Protocol (iSNS Protocol)

A protocol that is used by a host system to manage iSCSI targets and iSCSI discovery. iSCSI initiators use the iSNS Protocol to locate the appropriate storage resources.

inter-switch link (ISL)

The physical connection that carries a protocol for interconnecting multiple routers and switches in a storage area network (SAN).

I/O

See input/output.

I/O adapter

A functional unit or part of an I/O controller that connects devices to an I/O processor.

I/O bay

A dedicated bay in a Lenovo Flex System chassis in which a switch or pass-thru module can be installed.

I/O group

A collection of volumes and node relationships that present a common interface to host systems. Each pair of nodes is known as an input/output (I/O) group

I/O module

A type of module that includes switches and pass-thru modules.

IOPS

See input/output operations per second.

I/O throttling rate

The maximum rate at which an I/O transaction is accepted for a volume.

IP

See Internet Protocol.

IP address

A unique address for a device or logical unit on a network that uses the Internet Protocol standard.

IQN

See iSCSI qualified name.

iSCSI alias

An alternative name for the iSCSI-attached host.

iSCSI name

A name that identifies an iSCSI target adapter or an iSCSI initiator adapter. An iSCSI name can be an iSCSI qualified name (IQN) or an extended-unique identifier (EUI). Typically, this identifier has the following format: iqn.datecode.reverse domain.

iSCSI qualified name (IQN)

A unique name that identifies an iSCSI target adapter or an iSCSI initiator adapter as defined by the iSCSI standard (RFC 3722).

ISL

See inter-switch link.

ISL hop

Considering all pairs of node ports (N_ports) in a fabric and measuring distance only in terms of inter-switch links (ISLs) in the fabric, the number of ISLs traversed on the shortest route between the pair of nodes that are farthest apart in the fabric.

iSNS Protocol

See Internet Storage Name Service Protocol.

J

JBOD: See just a bunch of disks.
just a bunch of disks (JBOD): Hard disks that have not been configured according to the RAID system to increase fault tolerance and improve data access performance.

L

latency: The time interval between the initiation of a send operation by a source task and the completion of the matching receive operation by the target task. More generally, latency is the time between a task initiating data transfer and the time that transfer is recognized as complete at the data destination.
LBA: See logical block address.
LDAP: See Lightweight Directory Access Protocol.
least recently used (LRU): Pertaining to an algorithm used to identify and make available the cache space that contains the data that was least recently used.
light path diagnostics: A technology that provides a lighted path to failed or failing components to expedite hardware repairs.
Lightweight Directory Access Protocol (LDAP): An open protocol that uses TCP/IP to provide access to directories that support an X.500 model and that does not incur the resource requirements of the more complex X.500 Directory Access Protocol (DAP). For example, LDAP can be used to locate people, organizations, and other resources in an Internet or intranet directory.
local fabric: Storage area network (SAN) components (such as switches and cables) that connect the components (nodes, hosts, switches) of the local clustered system.
local/remote fabric interconnect: The storage area network (SAN) components that are used to connect the local and remote fabrics.
logical block address (LBA): The block number on a disk.
logical drive: See volume.
logical unit (LU): An entity to which Small Computer System Interface (SCSI) commands are addressed, such as a volume or managed disk (MDisk).
logical unit number (LUN): In the Small Computer System Interface (SCSI) standard, a unique identifier used to differentiate devices, each of which is a logical unit (LU).
longitudinal redundancy check (LRC): A method of error-checking during data transfer that involves checking parity on a row of binary digits that are members of a set that form a matrix.
LRC: See longitudinal redundancy check.
LRU: See least recently used.
LSI Logic Configuration Utility: A utility that is used to set the boot order of devices, add and remove devices from the boot list, and manage the RAID configuration.
LU: See logical unit.
LUN: See logical unit number.
LUN masking: A process where a host object can detect more LUNs than it is intended to use, and the device-driver software masks the LUNs that are not to be used by this host.

M

MAC: See Media Access Control.
managed disk (MDisk): A Small Computer System Interface (SCSI) logical unit (LU) that a Redundant Array of Independent Disks (RAID) controller provides and a clustered system manages. The MDisk is not visible to host systems on the storage area network (SAN).
managed disk group: See storage pool.
managed mode: An access mode that enables virtualization functions to be performed. See also access mode, image mode, unconfigured mode.
Managed Object Format (MOF): A language for defining Common Information Model (CIM) schemas.
management channel auto-discovery: A feature that enables a compute node to select a communication channel that is used for management traffic in a Lenovo Flex System chassis and find an alternative channel if the current channel becomes unavailable.
management domain: The scope of hardware that is under control of the IBM Flex System Manager management node. The management domain includes managed chassis and any devices that are managed by the management node, whether internal or external to a chassis.
management node: See IBM Flex System Manager management node.
management software: See IBM Flex System Manager management software.
master volume: In most cases, the volume that contains a production copy of the data and that an application accesses. See also auxiliary volume, relationship.
MB: See megabyte.
MBps: See megabytes per second.
MCAD: See management channel auto-discovery.
MDisk: See managed disk.
Media Access Control (MAC): In networking, the lower of two sublayers of the Open Systems Interconnection model data link layer. The MAC sublayer handles access to shared media, such as whether token passing or contention will be used.
megabyte (MB): For processor storage, real and virtual storage, and channel volume, 2 to the 20th power or 1,048,576 bytes. For disk storage capacity and communications volume, 1,000,000 bytes.
megabytes per second (MBps): A unit of data transfer rate equal to 1024 * 1024 bytes.
mesh: A network topology in which devices are connected with many redundant interconnections between network nodes. Every node has a connection to every other node in the network.
method: A way to implement a function on a class.
Metro Mirror: A function of the remote mirror and copy feature that constantly updates a secondary copy of a volume to match changes made to a source volume. See also Global Mirror.
midplane: A component in a Lenovo Flex System chassis that provides hot-swap power and data connections to compute nodes, I/O modules, Chassis Management Modules, power supplies, fan modules, and fan logic modules.
mirrored volume: A volume with two volume copies.
MOF: See Managed Object Format.

N

N_port: See node port.
namespace: The scope within which a Common Information Model (CIM) schema applies.
NAS: See network-attached storage.
nearline SAS drive: A drive that combines the high capacity data storage technology of a Serial Advanced Technology Attachment (SATA) drive with the benefits of a serial-attached SCSI (SAS) interface for improved connectivity.
network-attached storage (NAS): A task-optimized storage device directly attached to a network that operates independently of the general-purpose file servers.
Network File System (NFS): A protocol, developed by Sun Microsystems, Incorporated, that allows a computer to access files over a network as if they were on its local disks.
network interface controller (NIC): Hardware that provides the interface control between system main storage and external high-speed link (HSL) ports.
NFS: See Network File System.
NIC: See network interface controller.
node: A single processing unit within a system. For redundancy, nodes are deployed in pairs to make up a system.
node bay: A dedicated bay in a Lenovo Flex System chassis in which a compute node, storage node, or expansion unit can be installed.
node canister: A hardware unit that includes the node hardware, fabric and service interfaces, and serial-attached SCSI (SAS) expansion ports.
node port (N_port): A port that connects a node to a fabric or to another node. An N_port connects to a fabric port (F_port) or to the N_port of another node. An N_port handles creation, detection, and flow of message units to and from the connected systems. N_ports are end points in point-to-point links.
node rescue: The process by which a node that has no valid software installed on its hard disk drive can copy software from another node connected to the same Fibre Channel fabric.
nonvolatile RAM: Random access memory that retains its contents after electrical power to the device is shut off.
notification: A notice of an event, also referred to as an alert.
NVRAM: See nonvolatile RAM.

O

object: In object-oriented design or programming, a concrete realization (instance) of a class that consists of data and the operations associated with that data. An object contains the instance data that is defined by the class, but the class owns the operations that are associated with the data.
object model: An abstraction of a system's implementation.
object name: An object that consists of a namespace path and a model path. The namespace path provides access to the Common Information Model (CIM) implementation managed by the CIM Agent, and the model path provides navigation within the implementation.
object path: See object name.
oversubscription: The ratio of the sum of the traffic that is on the initiator network-device connections to the traffic that is on the most heavily loaded inter-switch links (ISLs), where more than one ISL is connected in parallel between these switches. The concept of oversubscription assumes a symmetrical network and a specific workload that is applied equally from all initiators and sent equally to all targets. See also symmetrical network.

P

partition: A logical division of storage on a fixed disk. See also virtualization.
partner node: The other node that is in the I/O group to which this node belongs.
partnership: In Metro Mirror or Global Mirror operations, the relationship between two clustered systems. In a clustered-system partnership, one system is defined as the local system and the other system as the remote system.
pend: A state between online and offline in which an object is making a transition from online to offline or from offline to online. The pend state is initiated when a pend event is sent by an online object or when an add event is sent by an offline object. See also un-pend.
PFA: See Predictive Failure Analysis (PFA).
point-in-time copy: The instantaneous copy that the FlashCopy service makes of the source volume. See also FlashCopy service.
port: The physical entity within a host, system, or storage system that performs the data communication (transmitting and receiving) over the Fibre Channel.
POST: See power-on self-test.
power-on self-test (POST): A series of internal diagnostic tests activated each time the system power is turned on.
power supply: A component that supplies power to other components in a system. Also referred to as a power supply unit.
power-supply bay: A dedicated bay in a Lenovo Flex System chassis in which a power supply can be installed.
power supply unit: A component that supplies power to other components in a system. Also referred to as a power supply.
Power Systems node: A compute node that comes with one or more IBM Power7 microprocessors and provides the function, reliability, and performance of a Power7 system. Contrast with X-Architecture node.
Predictive Failure Analysis (PFA): A scheduled evaluation of system data that detects and signals parametric degradation that might lead to functional failures.
primary: Pertaining to the active Chassis Management Module in a Lenovo Flex System chassis.
primary volume: In a stand-alone Metro Mirror or Global Mirror relationship, the target of write operations issued by the host application. See also relationship.
property: In the Common Information Model (CIM), an attribute that is used to characterize instances of a class.
PSU: See power supply unit.

Q

qualifier

A value that provides additional information about a class, association, indication, method, method parameter, instance, property, or reference.
A modifier that makes a name unique.

queue depth

The number of input/output (I/O) operations that can be run in parallel on a device.

quorum disk

A disk that contains a reserved area that is used exclusively for system management. The quorum disk is accessed when it is necessary to determine which half of the clustered system continues to read and write data. Quorum disks can either be MDisks or drives.

quorum index

The pointer that indicates the order used to resolve a tie. Nodes attempt to lock the first quorum disk (index 0), followed by the next disk (index 1), and finally the last disk (index 2). The tie is broken by the node that locks them first.

R

RAID

See Redundant Array of Independent Disks.

RAID 0

A data striping technique, which is commonly called RAID Level 0 or RAID 0 because of its similarity to common, RAID, data-mapping techniques. It includes no data protection, however, so, strictly speaking, the appellation RAID is a misnomer. RAID 0 is also known as data striping.

RAID 1

A form of storage array in which two or more identical copies of data are maintained on separate media.

RAID 10

A combination of RAID 0 and RAID 1 in which two identical copies of striped data exist, but there is no parity.

RAID 5

A form of parity RAID in which the disks operate independently, the data stripe size is no smaller than the exported block size, and parity check data is distributed across the array's disks.

RAID 6

A form of RAID that can continue to process read and write requests to all of an array's virtual disks in the presence of two concurrent disk failures.

RAID controller

See node canister.

real capacity

The amount of storage that is allocated to a volume copy from a storage pool.

rear LED card

A component in a Lenovo Flex System chassis that controls the LEDs on the rear information panel and stores the vital product data of the components in the chassis.

Recovery Guru

See fix procedure.

redundant ac-power switch

A device that provides input power redundancy by attaching a device to two independent power sources. If the main source becomes unavailable, the redundant ac-power switch automatically provides power from a secondary (backup) source. When power is restored, the redundant ac-power switch automatically changes back to the main power source.

Redundant Array of Independent Disks (RAID)

A collection of two or more physical disk drives that present to the host an image of one or more logical disk drives. In the event of a physical device failure, the data can be read or regenerated from the other disk drives in the array due to data redundancy. See also array.

redundant SAN

A storage area network (SAN) configuration in which any single component might fail, but connectivity between the devices within the SAN is maintained, possibly with degraded performance. This configuration is normally achieved by splitting the SAN into two independent, counterpart SANs. See also counterpart SAN.

rejected

Pertaining to a status condition that describes a node that the clustered-system software has removed from the working set of nodes in the clustered system.

relationship

In Metro Mirror or Global Mirror, the association between a master volume and an auxiliary volume. These volumes also have the attributes of a primary or secondary volume. See also auxiliary volume, master volume, primary volume, secondary volume.

remote copy

See Global Mirror.
See Metro Mirror.

remote fabric

In Global Mirror, the storage area network (SAN) components (switches and cables) that connect the components (nodes, hosts and switches) of the remote clustered system.

root squash

In the Network File System (NFS) Protocol, a reduction of the access rights for the remote superuser (root) when using identity authentication. The local user is the same as the remote user.

S

SAN: See storage area network.
SAS: See serial-attached SCSI.
schema: A group of object classes defined for and applicable to a single namespace.
SCP: See Secure Copy Protocol.
SCSI: See Small Computer System Interface.
SCSI back-end layer: The layer in a Small Computer System Interface (SCSI) network that performs the following functions: controls access to individual storage systems that are managed by the clustered system; receives requests from the virtualization layer, processes them, and sends them to managed disks; and addresses SCSI-3 commands to the storage systems on the storage area network (SAN).
SCSI front-end layer: The layer in a Small Computer System Interface (SCSI) network that receives I/O commands from hosts and provides the SCSI-3 interface to hosts. SCSI logical unit numbers (LUNs) are mapped to volumes in this layer as well. Thus, the layer converts SCSI read and write commands that are addressed to LUNs into commands that are addressed to specific volumes.
secondary volume: Pertinent to remote copy, the volume in a relationship that contains a copy of data written by the host application to the primary volume. See also relationship.
Secure Copy Protocol (SCP): The secure transfer of computer files between a local and a remote host or between two remote hosts, using the Secure Shell (SSH) protocol.
Secure Sockets Layer (SSL): A security protocol that provides communication privacy. With SSL, client/server applications can communicate in a way that is designed to prevent eavesdropping, tampering, and message forgery.
sequential volume: A volume that uses extents from a single managed disk (MDisk).
serial-attached SCSI (SAS): A data-transfer technology that moves data to and from computer storage devices. Serial-attached SCSI uses a point-to-point serial protocol, which replaces the traditional, parallel SCSI bus technology.
ServerGuide: A Lenovo deployment tool that detects installed optional hardware devices and installs a supported Microsoft Windows operating system and the applicable device drivers.
ServerGuide Scripting Toolkit: A collection of system-configuration tools and installation scripts that can be used to deploy software to compute nodes in a repeatable and predictable manner.
Service Advisor: A feature that notifies authorized service and support representatives when a designated serviceable event occurs.
service assistant: A user interface that services hardware independent of the storage system.
service-level reset: See service reset.
Service Location Protocol (SLP): An Internet protocol that identifies and uses network hosts without having to designate a specific network host name.
service request: A notification that is manually generated by a customer through the "Service requests and PMRs" website.
service reset: A hard restart or virtual reseat of a device in a Lenovo Flex System chassis.
Setup utility: The UEFI configuration tool that is included in compute nodes.
SFP transceiver: See small-form-factor pluggable transceiver.
shelf: A removable panel in a Lenovo Flex System chassis that separates two horizontally adjacent node bays from the two horizontally adjacent node bays immediately above or below.
shuttle: The portion of the Lenovo Flex System chassis housing on the rear of the chassis that contains the bays for hot-swap devices.
Simple Network Management Protocol (SNMP): A set of protocols for monitoring systems and devices in complex networks. Information about managed devices is defined and stored in a Management Information Base (MIB).
SLP: See Service Location Protocol.
Small Computer System Interface (SCSI): An ANSI-standard electronic interface that allows personal computers to communicate with peripheral hardware, such as disk drives, tape drives, CD-ROM drives, printers, and scanners faster and more flexibly than previous interfaces. See also target.
small-form-factor pluggable transceiver (SFP transceiver): An optical transceiver used to convert signals between optical fiber cables and switches.
SMI-S: See Storage Management Initiative Specification.
snapshot: An image backup type that consists of a point-in-time view of a volume.
SNIA: See Storage Networking Industry Association.
SNMP: See Simple Network Management Protocol.
soft shutdown: A process in which a system shuts down the operating system in an orderly way and possibly allows the user to save data before the system powers off. Contrast with hard shutdown.
solid-state drive (SSD): A data storage device that uses solid-state memory to store persistent data.
space-efficient VDisk: See thin-provisioned volume.
spare: An extra storage component, such as a drive or tape, that is predesignated for use as a replacement for a failed component.
spare goal: The optimal number of spares that are needed to protect the drives in the array from failures. The system logs a warning event when the number of spares that protect the array drops below this number.
SSD: See solid-state drive.
SSL: See Secure Sockets Layer.
stand-alone relationship: In FlashCopy, Metro Mirror, and Global Mirror, relationships that do not belong to a consistency group and that have a null consistency-group attribute.
standby: Pertaining to a redundant Chassis Management Module (CMM) in a Lenovo Flex System chassis that is available to assume the CMM functions if the primary CMM fails.
statesave: Binary data collection that is used in problem determination.
storage area network (SAN): A dedicated storage network tailored to a specific environment, combining servers, systems, storage products, networking products, software, and services.
storage bay: A dedicated bay in a Lenovo Flex System chassis in which a data storage device can be installed.
Storage Configuration Manager: A web-based device-management application that provides user and programmatic interfaces for configuring and monitoring multiple instances of different types of storage-related devices.
Storage Management Initiative Specification (SMI-S): A design specification developed by the Storage Networking Industry Association (SNIA) that specifies a secure and reliable interface with which storage management systems (SMSs) can identify, classify, monitor, and control physical and logical resources in a storage area network (SAN). The interface integrates the various devices to be managed in a SAN and the tools used to manage them.
Storage Manager Enterprise Management window: See graphical user interface.
Storage Networking Industry Association (SNIA): An alliance of computer vendors and universities that focus on developing and promoting industry standards for storage networks.
storage node: A component of a storage system that provides shared storage capacity to compute nodes. A storage node can include other storage nodes that work together.
storage pool: A collection of storage capacity that provides the capacity requirements for a volume.
storage system: A device, such as a Redundant Array of Independent Disks (RAID) controller, that creates and manages other storage devices.
strand: The serial-attached SCSI (SAS) connectivity of a set of drives within multiple enclosures. The enclosures can be either control enclosures or expansion enclosures.
striped: Pertaining to a volume that is created from multiple managed disks (MDisks) that are in the storage pool. Extents are allocated on the MDisks in the order specified.
subnet: See subnetwork.
subnetwork (subnet): A network that is divided into smaller independent subgroups, which still are interconnected.
switch: A network infrastructure component to which multiple nodes attach. Unlike a hub, a switch typically has internal bandwidth that is a multiple of link bandwidth and the ability to rapidly switch a node connection from one to another. A typical switch can accommodate several simultaneous full-link bandwidth transmissions between different pairs of nodes.
symmetrical network: A network in which all the initiators are connected at the same level and all the controllers are connected at the same level. See also oversubscription.
symmetric virtualization: A virtualization technique in which the physical storage, in the form of a Redundant Array of Independent Disks (RAID), is split into smaller chunks of storage known as extents. These extents are then concatenated, using various policies, to make volumes. See also asymmetric virtualization.
synchronous replication: A type of replication that delivers updates continuously and within the scope of source transactions. See also asynchronous replication.
syslog: A standard for transmitting and storing log messages from many sources to a centralized location to enhance system management.
system: A functional unit, consisting of one or more computers and associated software, that uses common storage for all or part of a program and also for all or part of the data necessary for the execution of the program. A system can be a stand-alone unit, or it can consist of multiple connected units. See also clustered system.
system board: In a compute node, the main circuit board that supports a variety of basic system devices, such as a keyboard or a mouse, and provides other basic system functions.
system-management processor: A component in a compute node that performs systems-management functions. In a Power Systems compute node, the system-management processor is referred to as the flexible system-management processor. In an X-Architecture computer node, the system-management processor is referred to as the integrated management module II.

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