With IBM Spectrum Virtualize, free space does not need to be maintained and managed in  each storage subsystem, which further increases capacity usage. Today, it is typical that open  systems run at less than 50% of the usable capacity that is provided by the RAID disk  subsystems.  The use of the installed raw capacity in the disk subsystems shows usage numbers of less  than 35%, depending on the RAID level that is used. A block-level virtualization solution, such  as IBM Spectrum Virtualize, can allow a significant increase to approximately 75 - 80%. IBM Spectrum Virtualize V8.2.1 is another step in the product line development that brings  new features and enhancements. The major software changes in subsequent code releases  are described in this section. V8.2.1 of the Spectrum Virtualize code brought the following changes: 1.3 Latest changes and enhancements GLYPH<SM590000> NVMe over Fibre Channel support on 16 Gb Fibre Channel adapters: Extends the  simplicity, efficiency, and end-to-end NVMe model where NVMe commands and structures  are transferred end to end, requiring no translations GLYPH<SM590000> Support for RDMA-based connections between nodes. This feature requires 25 GbE  adapters to be installed on the nodes. Expands the host connectivity options for those  storage arrays not initially covered by 8.2. GLYPH<SM590000> Single copy VDisk expand with format: Enables administrators to expand a VDisk without  migrating the data off and back on. GLYPH<SM590000> Added support for SafeNet KeySecure encryption key server. GLYPH<SM590000> Improvements to call home with email notifications. GLYPH<SM590000> IBM Spectrum Insights: Provides a call home protocol that uses IBM IP to deliver a more  robust path and higher bandwidth and higher frequency data transmission, with  end-to-end confirmation of receipt. GLYPH<SM590000> 64 K host mappings: Increased from the previous limitation of 20 K. GLYPH<SM590000> Support for host login information for Ethernet-attached hosts. GLYPH<SM590000> Support for iSCSI extensions over RDMA (iSER) host attach enhancements. GLYPH<SM590000> Full IP-based quorum: Support for administrators looking to consolidate their infrastructure  over Ethernet. 6  Implementing the IBM Storwize V7000 with IBM Spectrum Virtualize V8.2.1