Mirrored volume Node canister Node rescue NPIV Object Storage Oversubscription Over provisioned Over provisioned ratio Parent pool Partnership In Metro Mirror or Global Mirror operations, the relationship between two clustered systems.  In a clustered-system partnership, one system is defined as the local system and the other  system as the remote system. Parent pools receive their capacity from MDisks. All MDisks in a pool are split into extents of  the same size. Volumes are created from the extents that are available in the pool. You can  add MDisks to a pool at any time either to increase the number of extents that are available  for new volume copies or to expand existing volume copies. The system automatically  balances volume extents between the MDisks to provide the best performance to the  volumes. See “Capacity” on page 771. See “Capacity” on page 771. Oversubscription refers to the ratio of the sum of the traffic on the initiator N-port connections  to the traffic on the most heavily loaded ISLs, where more than one connection is used  between these switches. Oversubscription assumes a symmetrical network, and a specific  workload that is applied equally from all initiators and sent equally to all targets. A  symmetrical network means that all the initiators are connected at the same level, and all the  controllers are connected at the same level. Object Storage is a general term that refers to the entity in which Cloud Object Storage  organizes, manages, and stores with units of storage or just  objects . N_Port ID Virtualization (NPIV) is a Fibre Channel feature whereby multiple Fibre Channel  node port (N_Port) IDs can share a single physical N_Port. The process by which a node with no valid software is installed on its hard disk drive can copy  software from another node connected to the same Fibre Channel fabric. A node canister is a hardware unit that includes the node hardware, fabric and service  interfaces, and serial-attached SCSI (SAS) expansion ports. Node canisters are specifically  recognized on IBM Storwize products. In SVC, all these components are spread within the  whole system chassis, so we usually do not consider node canisters in SVC, but just the node  as a whole. A mirrored volume is a single virtual volume that has two physical volume copies. The primary  physical copy is known within the IBM Storwize V7000 as  copy 0  and the secondary copy is  known within the IBM Storwize V7000 as  copy 1 . Appendix C. Terminology  781