This option has two variations: This function can be used with multitarget, cascaded, and incremental FlashCopy. Consistency groups address the issue where application data is on multiple volumes.  By placing the FlashCopy relationships into a consistency group, commands can be  issued against all of the volumes in the group. This action provides a consistent  point-in-time copy of all of the data, even if it is on a physically separate volume. FlashCopy mappings can be members of a consistency group, or they can be operated  in a stand-alone manner, not as part of a consistency group. FlashCopy commands  can be issued to a FlashCopy consistency group, which affects all FlashCopy  mappings in the consistency group, or to a single FlashCopy mapping if it is not part of  a defined FlashCopy consistency group. Provides a  synchronous  remote mirroring function up to approximately 300 km  (186.4 miles) between sites. Because the host I/O only completes after the data is cached  at both locations, performance requirements might limit the practical distance. Metro  Mirror provides fully synchronized copies at both sites with zero data loss after the initial  copy is completed. Metro Mirror can operate between multiple IBM Storwize systems and  IBM SAN Volume Controllers. Provides a long-distance  asynchronous  remote mirroring function up to approximately  8,000 km (4,971 miles) between sites. With Global Mirror, the host I/O completes locally  and the changed data is sent to the remote site later. This feature maintains a consistent  recoverable copy of data at the remote site, which lags behind the local site. Global Mirror  can operate between multiple IBM Storwize systems and IBM SAN Volume Controllers. IBM Storwize V7000 provides a data migration function that can be used to import external  storage systems into the IBM Storwize V7000 system. The following tasks can be  accomplished: IBM Storwize V7000 Gen2 and IBM Storwize Gen2+ provide optional encryption of  data-at-rest functionality, which protects against the potential exposure of sensitive user  data and user metadata that is stored on discarded, lost, or stolen storage devices.  Encryption can only be enabled and configured on enclosures that support encryption. Starting with IBM Spectrum Virtualize V7.6, IBM Spectrum Virtualize offers  software-enabled encryption (hardware encryption was introduced in V7.4), which  includes encryption of internal or external storage. Encryption keys now can be stored  either on USB flash drives, IBM Security Key Lifecycle Manager server, or both. GLYPH<SM590000> Software Encryption – Migrate data from other back-end storage to IBM Storwize V7000-managed storage. – Move volumes to rebalance a changed workload. – Move volumes nondisruptively onto a newly installed storage system. GLYPH<SM590000> External virtualization GLYPH<SM590000> Global Mirror GLYPH<SM590000> Metro Mirror – Consistency groups GLYPH<129> Space-efficient target with no background copy GLYPH<129> Space-efficient source and target with background copy Copies only the allocated space. Copies only the space that is used for changes between the source and target, and  is referred to as a  snapshot . Chapter 2. System overview  17