Documentation/scsi/sd-parameters.txt

   1 Linux SCSI Disk Driver (sd) Parameters
   2 ======================================
   3
   4 cache_type (RW)
   5 ---------------
   6 Enable/disable drive write & read cache.
   7
   8  cache_type string          | WCE RCD | Write cache | Read cache
   9 ----------------------------+---------+-------------+------------
  10  write through              | 0   0   | off         | on
  11  none                       | 0   1   | off         | off
  12  write back                 | 1   0   | on          | on
  13  write back, no read (daft) | 1   1   | on          | off
  14
  15 To set cache type to "write back" and save this setting to the drive:
  16
  17   # echo "write back" > cache_type
  18
  19 To modify the caching mode without making the change persistent, prepend
  20 "temporary " to the cache type string. E.g.:
  21
  22   # echo "temporary write back" > cache_type