Striped Support Assistance Symmetric virtualization Synchronous replication Tie-break Thin-provisioned volume Thin provisioning Thin provisioning savings Throttles Transparent Cloud Tiering Total capacity savings Pertaining to a volume that is created from multiple MDisks that are in the storage pool.  Extents are allocated on the MDisks in the order specified. A function that is used to provide support personnel remote access to the system to perform  troubleshooting and maintenance tasks. Symmetric virtualization is a virtualization technique in which the physical storage, in the form  of a RAID, is split into smaller chunks of storage known as extents. These extents are then  concatenated, by using various policies, to make volumes. See also “Asymmetric  virtualization” on page 796. Synchronous replication is a type of replication in which the application write operation is  made to both the source volume and target volume before control is given back to the  application. See also “Asynchronous replication” on page 796. In a case of a cluster split in 2 groups of nodes, tie-break is a role of a quorum device used to  decide which group continues to operate as the system, handling all I/O requests. A thin-provisioned volume is a volume that allocates storage when data is written to it. Thin provisioning refers to the ability to define storage, usually a storage pool or volume, with  a “logical” capacity size that is larger than the actual physical capacity that is assigned to that  pool or volume. Therefore, a thin-provisioned volume is a volume with a virtual capacity that  differs from its real capacity. Before SVC V6.1, this thin-provisioned volume was known as  space efficient . See “Capacity” on page 797. Throttling is a mechanism to control the amount of resources that are used when the system  is processing I/Os on supported objects. The system supports throttles on hosts, host  clusters, volumes, copy offload operations, and storage pools. If a throttle limit is defined, the  system either processes the I/O for that object, or delays the processing of the I/O to free  resources for more critical I/O operations. Transparent Cloud Tiering is a separately installable feature of IBM Spectrum Scale™ that  provides a native cloud storage tier. See “Capacity” on page 797. Appendix C. Terminology  813