Logical subsystems

A logical subsystem (LSS) enables one or more host I/O interfaces to access a set of devices. You must create an LSS before you can associate count key data (CKD) volumes to the LSS.

Note: LSS is synonymous with logical control unit (LCU) and subsystem identification (SSID).

LSS properties

You can view the properties of an LSS in the Volumes by LSS table or the LSS Properties window.

ID: The system-issued ID number of the LSS.
SSID: The subsystem identifier (SSID) of the LSS within a z/OS® environment.
LSS type: The count key data (CKD) LSS type.
Node: The processor node (Node 0 or Node 1) that handles the LSS I/O.
Address usage: The number of base volumes, aliases, and available addresses for the LSS.
Scope: The multitenancy scope of the LSS.
Multitenancy, in storage terms, is a system architecture in which a hardware component or software application services the needs of more than one customer. Each customer is referred to as a tenant. Tenants can be given the ability to customize and run functions for defined parts of the infrastructure to which they are granted permission. This defined area is the customer's multitenancy scope. Multitenancy generally prevents a host or user from initiating a Copy Services operation that would cross the tenant’s domain boundaries.
Address group: The address group of the LSS that is assigned by the system.
Consistency group: The Remote Mirror and Copy consistency group setting for the LSS.; Consistency groups are used to help create a consistent point-in-time copy across multiple volumes, and even across multiple DS8000® storage systems.
Consistency group timeout: The time (measured in seconds) that an LSS consistency group volume displays as busy after the reporting of an error that suspends remote mirroring and Copy Services functions.
Concurrent copy session timeout: The concurrent copy session timeout parameter (measured in seconds) that a CKD LSS in a concurrent copy session displays as busy before a concurrent copy session is suspended.
Global Mirror session timeout: The Global Mirror session timeout parameter (as measured in seconds) that a CKD LSS displays as busy before the Global Mirror session is suspended.
Critical heavy mode: The critical heavy mode controls the behavior of the remote copy and mirror pairs that are associated with a CKD volume on the LSS.