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Glossary

A
ACL
Access control list.
active/active configuration
  • In the Data ONTAP 7.2 and 7.3 release families, a pair of storage systems or V-Series systems (sometimes called nodes) configured to serve data for each other if one of the two systems stops functioning. Also sometimes referred to as active/active pairs.
  • In the Data ONTAP 8.x release family, this functionality is referred to as a high-availability (HA) configuration or an HA pair.
  • In the Data ONTAP 7.1 release family and earlier releases, this functionality is referred to as a cluster.
address resolution
The procedure for determining an address corresponding to the address of a LAN or WAN destination.
admin Vserver
In Data ONTAP operating in Cluster-Mode, a Vserver that has overall administrative access to all objects in the cluster, including all objects owned by other Vservers, but does not provide data access to clients or hosts.
administration host
A client computer that is used to manage a storage system through a Telnet or Remote Shell connection.
Application Program Interface (API)
A language and message format used by an application program to communicate with the operating system or some other system, control program, or communications protocol.
authentication
The process of verifying the identity of a user who is logging in to a computer system.
AutoSupport
An integrated technology that triggers email messages from the customer site to technical support or another specified email recipient when there are any failures in Unified Manager services. These messages contain information such as feature usage metrics, configuration and user settings, system health, and so on.
B
big-endian
A binary data format for storage and transmission in which the most significant byte comes first.
C
caching module
A Flash Cache 2, Flash Cache, or Performance Acceleration Module (PAM) PCIe-based, memory module that optimizes the performance of random read-intensive workloads by functioning as an intelligent external read cache. This hardware works in tandem with the WAFL External Cache software component of Data ONTAP.
CIFS share
  • In Data ONTAP, a directory or directory structure that has been made available to network users and can be mapped to a drive letter on a CIFS client. Also known simply as a share.
  • In OnCommand Insight (formerly SANscreen suite), a service exposed from a NAS device to provide file-based storage through the CIFS protocol. CIFS is mostly used for Microsoft Windows clients, but many other operating systems can access CIFS shares as well.
CLI
command-line interface. The storage system prompt is an example of a command-line interface.
client
A workstation or PC in a client-server architecture; that is, a computer system or process that requests services from and accepts the responses of another computer system or process.
cluster
  • In clustered Data ONTAP 8.x, a group of connected nodes (storage systems) that share a namespace and that you can manage as a single virtual server or multiple virtual servers, providing performance, reliability, and scalability benefits.
  • In the Data ONTAP 7.1 release family and earlier releases, a pair of storage systems (sometimes called nodes) configured to serve data for each other if one of the two systems stops functioning.
  • In the Data ONTAP 7.3 and 7.2 release families, this functionality is referred to as an active/active configuration.
  • For some storage array vendors, cluster refers to the hardware component on which host adapters and ports are located. Some storage array vendors refer to this component as a controller.
cluster Vserver
Previous name for a data Vserver. See data Vserver.
Common Internet File System (CIFS)
Microsoft's file-sharing networking protocol that evolved from SMB.
community
A logical relationship between an SNMP agent and one or more SNMP managers. A community is identified by name, and all members of the community have the same access privileges.
console
The physical or virtual terminal that is used to monitor and control a storage system.
Copy-On-Write (COW)
The technique for creating Snapshot copies without consuming excess disk space.
D
data Vserver
In clustered Data ONTAP, a virtual server that facilitates data access from the cluster; the hardware and storage resources of the cluster are dynamically shared by data Vservers within a cluster. Previously referred to as a cluster Vserver.
degraded mode
The operating mode of a storage system when a disk in the RAID group fails or the batteries on the NVRAM card are low.
disk ID number
The number assigned by the storage system to each disk when it probes the disks at startup.
disk sanitization
A multiple write process for physically obliterating existing data on specified disks in such a manner that the obliterated data is no longer recoverable by known means of data recovery.
disk shelf
A shelf that contains disk drives and is attached to a storage system.
E
emulated storage system
A software copy of a failed storage system that is hosted by its takeover storage system. The emulated storage system appears to users and administrators to be a functional version of the failed storage system. For example, it has the same name as the failed storage system.
Ethernet adapter
An Ethernet interface card.
expansion card
A SCSI card, NVRAM card, network card, hot-swap card, or console card that plugs into a storage system expansion slot. Sometimes called an adapter.
expansion slot
The slots on the storage system board into which you insert expansion cards.
F
failed storage system
A physical storage system that has ceased operating. In a high-availability configuration, it remains the failed storage system until a giveback succeeds.
Flash Cache/Flash Cache 2
The two members of the family of PCIe-based, solid state memory modules that optimize the performance of random read-intensive workloads by functioning as an intelligent external read cache. The Flash Cache 2 module is the successor of the Flash Cache module, which is the successor of the Performance Acceleration Module (PAM). This hardware works in tandem with the WAFL External Cache software component of Data ONTAP.
G
giveback
The technology that enables two storage systems to return control of each other's data after the issues that caused a controller failover are resolved.
global namespace
See namespace.
group
In Data ONTAP operating in 7-Mode, a group of users defined in the storage system’s /etc/group file.
Group ID (GID)
The number used by UNIX systems to identify groups.
H
HA (high availability)
  • In Data ONTAP 8.x, the recovery capability provided by a pair of nodes (storage systems), called an HA pair, that are configured to serve data for each other if one of the two nodes stops functioning.
  • In the Data ONTAP 7.3 and 7.2 release families, this functionality is referred to as an active/active configuration.
HA pair
  • In Data ONTAP 8.x, a pair of nodes whose controllers are configured to serve data for each other if one of the two nodes stops functioning.

    Depending on the system model, both controllers can be in a single chassis, or one controller can be in one chassis and the other controller can be in a separate chassis.

  • In the Data ONTAP 7.3 and 7.2 release families, this functionality is referred to as an active/active configuration.
heartbeat
A repeating signal transmitted from one storage system to the other that indicates that the storage system is in operation. Heartbeat information is also stored on disk.
hot swap
The process of adding, removing, or replacing a disk while the storage system is running.
hot swap adapter
An expansion card that makes it possible to add or remove a hard disk with minimal interruption to file system activity.
I
inode
A data structure containing information about files on a storage system and in a UNIX file system.
interrupt switch
A switch on some storage system front panels used for debugging purposes.
L
LAN Emulation (LANE)
The architecture, protocols, and services that create an Emulated LAN using ATM as an underlying network topology. LANE enables ATM-connected end systems to communicate with other LAN-based systems.
M
Maintenance mode
An option when booting a storage system from a system boot disk. Maintenance mode provides special commands for troubleshooting hardware and configuration.
MultiStore
In Data ONTAP operating in 7-Mode, an optional software product that enables you to partition the storage and network resources of a single storage system so that it appears as multiple storage systems on the network.
N
namespace
In network-attached storage (NAS) environments, a collection of files and path names to the files.
NDMP
Network Data Management Protocol. A protocol that allows storage systems to communicate with backup applications and provides capabilities for controlling the robotics of multiple tape backup devices.
network adapter
An Ethernet, FDDI, or ATM card.
node Vserver
In Data ONTAP operating in Cluster-Mode, a Vserver that is restricted to operation in a single node of the cluster at any one time, and provides administrative access to some objects owned by that node. A node Vserver does not provide data access to clients or hosts.
normal mode
The state of a storage system when there is no takeover in the high-availability configuration.
NVMEM
nonvolatile memory.
NVRAM cache
Nonvolatile RAM in a storage system, used for logging incoming write data and NFS requests. Improves system performance and prevents loss of data in case of a storage system or power failure.
NVRAM card
An adapter that contains the storage system’s NVRAM cache.
NVRAM mirror
A synchronously updated copy of the contents of the storage system NVRAM (nonvolatile random access memory) contents kept on the partner storage system.
P
PAM (Performance Acceleration Module)
A PCIe-based, DRAM memory module that optimizes the performance of random read-intensive workloads by functioning as an intelligent external read cache. This hardware is the predecessor of the Flash Cache module and works in tandem with the WAFL External Cache software component of Data ONTAP.
panic
A serious error condition causing the storage system or V-Series system to halt. Similar to a software crash in the Windows system environment.
parity disk
The disk on which parity information is stored for a RAID4 disk drive array. In RAID groups using RAID-DP protection, two parity disks store the parity and double-parity information. Used to reconstruct data in failed disk blocks or on a failed disk.
partner mode
The method you use to communicate through the command-line interface with a virtual storage system during a takeover.
partner node
From the point of view of the local node (storage system), the other node in a high-availability configuration.
Performance Acceleration Module (PAM)
See PAM (Performance Acceleration Module).
POST
Power-on self-tests. The tests run by a storage system after the power is turned on.
Q
qtree
A special subdirectory of the root of a volume that acts as a virtual subvolume with special attributes.
R
RAID
Redundant Array of Independent Disks. A technique that protects against disk failure by computing parity information based on the contents of all the disks in an array. Storage systems use either RAID4, which stores all parity information on a single disk, or RAID-DP, which stores all parity information on two disks.
RAID disk scrubbing
The process in which a system reads each disk in the RAID group and tries to fix media errors by rewriting the data to another disk area.
S
SCSI adapter
An expansion card that supports SCSI disk drives and tape drives.
SCSI address
The full address of a disk, consisting of the disk’s SCSI adapter number and the disk’s SCSI ID, such as 9a.1.
SCSI ID
The number of a disk drive on a SCSI chain (0 to 6).
serial adapter
An expansion card for attaching a terminal as the console on some storage system models.
serial console
An ASCII or ANSI terminal attached to a storage system’s serial port. Used to monitor and manage storage system operations.
SFO
See storage failover (SFO).
SID
Security identifier used by the Windows operating system.
Snapshot copy
An online, read-only copy of an entire file system that protects against accidental deletions or modifications of files without duplicating file contents. Snapshot copies enable users to restore files and to back up the storage system to tape while the storage system is in use.
storage failover (SFO)
In Data ONTAP operating in Cluster-Mode, the method of ensuring data availability by transferring the data service of a failed node to another node in an HA pair. Transfer of data service is often transparent to users and applications. In Data ONTAP 7.2 and later, and in Data ONTAP operating in 7-Mode, the failover method is called controller failover.
T
takeover
The emulation of the failed node identity by the takeover node in a high-availability configuration; the opposite of giveback.
takeover mode
The method you use to interact with a node (storage system) when it has taken over its partner. The console prompt indicates when the node is in takeover mode.
takeover node
A node (storage system) that remains in operation after the other node stops working and that hosts a virtual node that manages access to the failed node disk shelves and network connections. The takeover node maintains its own identity and the virtual node maintains the failed node identity.
trap
An asynchronous, unsolicited message sent by an SNMP agent to an SNMP manager indicating that an event has occurred on the storage system.
U
UID
user identification number.
Unicode
A 16-bit character set standard. It was designed and is maintained by the nonprofit consortium Unicode Inc.
V
vFiler unit
In Data ONTAP operating in 7-Mode, a virtual storage system that you create using MultiStore, which enables you to partition the storage and network resources of a single storage system so that it appears as multiple storage systems on the network.
volume
A file system.
Vserver
In Data ONTAP operating in Cluster-Mode, a virtual server that provides network access through unique network addresses, that might serve data out of a distinct namespace, and that is separately administrable from the rest of the cluster. There are three types of Vservers—admin, data, and node—but unless there is a specific need to identify the type of Vserver, Vserver usually refers to data Vserver.
W
WAFL
Write Anywhere File Layout. A file system designed for the storage system to optimize write performance.
WAFL External Cache
On a storage system that has a Performance Acceleration Module (PAM), Flash Cache, or Flash Cache 2 module installed, this cache improves storage system performance by reducing the number of disk reads. Sometimes referred to as WAFL extended cache.
WINS
Windows Internet Name Service.
workgroup
A collection of computers running Windows NT or Windows for Workgroups that is grouped for browsing and sharing.