780 Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1
Local and remote fabric interconnect
The local fabric interconnect and the remote fabric interconnect are the SAN components that 
are used to connect the local and remote fabrics. Depending on the distance between the two 
fabrics, they can be single-mode optical fibers that are driven by long wave (LW) gigabit 
interface converters (GBICs) or Small Form-factor Pluggables (SFPs), or more sophisticated 
components, such as channel extenders or special SFP modules that are used to extend the 
distance between SAN components.
Local fabric
The local fabric is composed of SAN components (switches, cables, and so on) that connect 
the components (nodes, hosts, and switches) of the local cluster together.
Logical unit and logical unit number
The logical unit (LU) is defined by the SCSI standards as a LUN. LUN is an abbreviation for 
an entity that exhibits disk-like behavior, such as a volume or an MDisk.
Machine signature
A string of characters that identifies a system. A machine signature might be required to 
obtain a license key.
Managed disk
An MDisk is a SCSI disk that is presented by a RAID controller and managed by IBM Storwize 
V7000. The MDisk is not visible to host systems on the SAN. 
Managed disk group (storage pool)
See “Storage pool (managed disk group)” on page 786.
Managed mode
An access mode that enables virtualization functions to be performed. See also “Image 
mode” on page 778 and “Unmanaged mode” on page 787.
Maximum replication delay
Maximum replication delay is the number of seconds that Metro Mirror or Global Mirror 
replication can delay a write operation to a volume.
Master volume
In most cases, the volume that contains a production copy of the data and that an application 
accesses. See also “Auxiliary volume” on page 770, and “Relationship” on page 784.
Metro Global Mirror
Metro Mirror Global is a cascaded solution where Metro Mirror synchronously copies data to 
the target site. This Metro Mirror target is the source volume for Global Mirror that 
asynchronously copies data to a third site. This solution has the potential to provide disaster 
recovery with no data loss at Global Mirror distances when the intermediate site does not 
participate in the disaster that occurs at the production site.
Metro Mirror
Metro Mirror (MM) is a method of synchronous replication that maintains data consistency 
across multiple volumes within the system. Metro Mirror is generally used when the write 
latency that is caused by the distance between the source site and target site is acceptable to 
application performance.