[linux-2.6-block.git] / Documentation / scsi / sd-parameters.txt

Linux SCSI Disk Driver (sd) Parameters
======================================

cache_type (RW)
---------------
Enable/disable drive write & read cache.

 cache_type string          | WCE RCD | Write cache | Read cache
----------------------------+---------+-------------+------------
 write through              | 0   0   | off         | on
 none                       | 0   1   | off         | off
 write back                 | 1   0   | on          | on
 write back, no read (daft) | 1   1   | on          | off

To set cache type to "write back" and save this setting to the drive:

  # echo "write back" > cache_type

To modify the caching mode without making the change persistent, prepend
"temporary " to the cache type string. E.g.:

  # echo "temporary write back" > cache_type
Commit	Line	Data
18d595bf WZ	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