778 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
Hot extent
A hot extent is a frequently accessed volume extent that gets a performance benefit if it is 
moved from an HDD onto a Flash Disk.
Hot Spare node (SVC only)
Hot Spare Node is an online SVC node defined in a cluster, but not in any IO group. During a 
failure of any of online nodes in any IO group of cluster, it is automatically swapped with this 
spare node. After the recovery of an original node has finished, the spare node returns to the 
standby spare status. This feature is not available for IBM Storwize V7000.
HyperSwap
Pertaining to a function that provides continuous, transparent availability against storage 
errors and site failures, and is based on synchronous replication.
Image mode
Image mode is an access mode that establishes a one-to-one mapping of extents in the 
storage pool (existing LUN or (image mode) MDisk) with the extents in the volume. See also 
“Managed mode” on page 780 and “Unmanaged mode” on page 787.
Image volume
An image volume is a volume in which a direct block-for-block translation exists from the 
MDisk to the volume.
I/O Group
Each pair of IBM Storwize V7000 canisters is known as an input/output (I/O) Group. An I/O 
Group has a set of volumes that are associated with it that are presented to host systems. 
Each V7000 canister is associated with exactly one I/O Group. The canister in an I/O Group 
provide a failover and failback function for each other.
Internal storage
Internal storage refers to an array of MDisks and drives that are held in IBM Storwize V7000 
enclosures.
Internet Small Computer System Interface qualified name
iSCSI qualified name (IQN) refers to special names that identify both iSCSI initiators and 
targets. IQN is one of the three name formats that is provided by iSCSI. The IQN format is 
iqn.<yyyy-mm>.<reversed domain name>. For example, the default for a Storwize V7000 
canister can be in the following format:
iqn.1986-03.com.ibm:2076.<clustername>.<nodename>
Internet storage name service
The internet storage name service (iSNS) protocol that is used by a host system to manage 
iSCSI targets and the automated iSCSI discovery, management, and configuration of iSCSI 
and FC devices. It was defined in Request for Comments (RFC) 4171.
Inter-switch link hop
An inter-switch link (ISL) is a connection between two switches and counted as one ISL hop. 
The number of hops is always counted on the shortest route between two N-ports (device 
connections). In an IBM Storwize V7000 environment, the number of ISL hops is counted on 
the shortest route between the pair of canister that are farthest apart. The V7000 supports a 
maximum of three ISL hops.