7.7.1 Methods to identify a disk for use as a virtual SCSI disk 7.8 Windows hosts 7.8.1 Clustering and reserves 7.8.2 Tunable parameters The VIOS uses the following methods to uniquely identify a disk for use as a virtual SCSI  disk: Each of these methods can result in different data formats on the disk. The preferred disk  identification method for volumes is the use of UDIDs. To release new enhancements more quickly, the newer hardware architectures are tested  only on the SDDDSM code stream. Therefore, only SDDDSM packages are available. For Microsoft Windows 2016, and Microsoft Windows 2012, download the latest version of  SDDDSM from this website: IBM Support - SDDDSM Windows SDDDSM uses the persistent reserve functions to implement Windows clustering. A  stand-alone Windows host does not use reserves. When SDDDSM is installed, the reserve and release functions are converted into the  appropriate persistent reserve and release equivalents to allow load balancing and  multipathing from each host. With Windows operating systems, the queue-depth settings are the responsibility of the host  adapters. They are configured through the BIOS setting. Configuring the queue-depth  settings varies from vendor to vendor. For more information about configuring your specific  cards, see “Hosts running the Microsoft Windows Server operating system” in IBM  FlashSystem 9100 Knowledge Center Queue depth is also controlled by the Windows application program. The application program  controls the number of I/O commands that it allows to be outstanding before waiting for  completion. You might have to adjust the queue depth that is based on the overall I/O group  queue depth calculation, as described in Chapter 5, “Volumes” on page 101.  IBM FlashSystem 9100 Knowledge Center - Windows Hosts Chapter 7. Hosts  261 GLYPH<SM590000> Unique device identifier (UDID) GLYPH<SM590000> IEEE volume identifier GLYPH<SM590000> Physical volume identifier (PVID)