text: **7.8.23 Tracing a volume from a host back to its physical disks**
  
  In some cases, you might need to verify exactly which physical disks are used to store data of 
  a volume. This information is not directly available to the host; however, it might be obtained 
  by using a sequence of queries. 
  
  The first step is to unequivocally map a logical device seen by the host to a volume that is 
  presented by the storage system. The best volume characteristics for this purpose is the 
  volume ID. This ID is available to the operating system in the Vendor Specified Identifier field 
  of page 0x80 or 0x83 (vital product data, VPD), which the storage device sends in response 
  to SCSI INQUIRY command from the host. 
  
  In practice, the ID can be obtained from the multipath driver in the operating system. After the 
  volume ID is known, it can be used to identify physical location of data. 
  
  **Note:**For sequential and image mode volumes, a volume copy is mapped to exactly one 
  MDisk. This configuration often is not the case for stripped volumes, unless volume size is 
  not greater than an extent size. Therefore, a single stripped volume uses multiple mDisks 
  in a typical case. 