To understand the concepts in this document, you might need to know the terms defined here.
General storage system terminology
- Storage systems that run Data ONTAP are sometimes referred to as filers, appliances, storage
appliances, or systems. The name of the FilerView graphical user interface for Data ONTAP reflects one of these common usages.
- Controller or storage controller refers to the component of a storage system that runs the Data ONTAP operating system and controls its disk subsystem. Controllers or storage controllers are also sometimes called storage appliances, appliances, storage engines, heads, CPU modules, or controller modules.
Active/active configuration terminology
- An active/active configuration is a pair of storage systems configured to serve data for each other if one of the two systems becomes impaired. In Data ONTAP documentation and other information resources, active/active configurations are sometimes also referred to as clusters or active/active pairs.
- When in an active/active configuration, systems are often called nodes. One node is sometimes called the local node, and the other node is called the partner node or remote node.
- Controller failover, also referred to as cluster failover or CFO, refers to the technology that enables two storage systems to take over each other's data, thus improving data availability.
- Fabric-attached MetroCluster refers to an active/active configuration
running the syncmirror_local and cluster_remote licenses, where the nodes are attached to two pairs of Fibre Channel switches, and they are separated by more than 500 meters.
- FC direct-attached topologies
are topologies in which the hosts are directly attached to the storage system. Direct-attached systems do not use a fabric or FC switches.
- FC dual fabric topologies
are topologies in which each host is attached to two physically independent fabrics that are connected to
storage systems. Each independent fabric can consist of multiple FC switches. A fabric that is zoned into two logically independent fabrics is not a dual fabric connection.
- FC single fabric topologies
are topologies in which the hosts are attached to the storage systems through a single FC
fabric. The fabric can consist of multiple FC switches.
- iSCSI direct-attached topologies
are topologies in which the hosts are directly attached to the storage controller. Direct-attached systems do not use networks or Ethernet switches.
- iSCSI network-attached topologies
are topologies in which the hosts are attached to storage controllers through Ethernet switches.
Networks can contain multiple Ethernet switches in any configuration.
- Mirrored active/active configuration is similar to the standard active/active configuration, except that there are two copies, or plexes, of the data. This is also called data mirroring.
- Remote storage refers to the storage that is accessible to the local node, but is at the location of the remote node.
- Single storage controller configurations
are topologies in which there is only one storage controller used.
Single storage controller configurations have a single point of failure and do not support cfmodes
in FC SAN configurations.
- Standard active/active configuration refers to a configuration set up so that one node automatically takes over for its partner when the partner node becomes impaired.
- Stretch MetroCluster refers to an active/active configuration
running the syncmirror_local and cluster_remote licenses, where the nodes are separated by up to 500 meters, and no switches are used between the nodes. This configuration is also sometimes called a nonswitched MetroCluster.
Storage hardware terminology
- AT-FCX refers to an enhanced FC-AL to Serial ATA (SATA) bridge used in some disk shelves.
- Disk shelf refers to a unit of the disk subsystem component of the storage system.
- ESH (Embedded Switching Hub) disk shelf module refers to a component that provides a means of managing an FC-AL loop in an intelligent manner, such that a single drive failure does not take down the loop. It also contains the enclosure services processor, which communicates the environmental data of the disk shelf.
- ESH2 disk shelf module refers to a second-generation ESH module.
- ESH4 disk shelf module refers to a third-generation ESH module.
- FC HBA for Disk or FC HBA refers to the Fibre Channel host bus adapter that connects the node to the switch or to the disks.
- Host bus adapters
(HBAs) are FC or iSCSI I/O adapters that connect a host I/O bus to a
computer's memory system in SCSI environments.
- LRC (Loop Resiliency Circuit) disk shelf module refers to a component that keeps the Fibre Channel-Arbitrated Loop (FC-AL) intact during the addition and removal of disks within a disk shelf. It also contains the enclosure services processor, which communicates the environmental data of the disk shelf.
- Target adapters
are I/O adapters that reside on the storage system and receive data from the
host. A target adapter that is already attached to the storage system controller is an onboard
adapter; a target adapter that is separately installed in one of the system’s available slots
is a target expansion adapter. Onboard adapters can also be configured to operate in initiator
mode in which they connect to disk shelves. Most storage systems also support the use of
expansion adapters that operate in initiator mode.
General terms
- The term enter means pressing one or more keys on the keyboard and then pressing the Enter key, or clicking in a field in a graphical interface and typing information into it.
- The term type means pressing one or more keys on the keyboard.
