From 18d595bf9de99a0f092d8522da42df8b09ef5c2f Mon Sep 17 00:00:00 2001 From: Weiping Zhang Date: Mon, 26 Feb 2018 22:08:28 +0800 Subject: scsi: sd: Documentation: add sd-parameters.txt Add a file for documenting SCSI sd module parameters and describe the cache_type setting. [mkp: tweaked text a bit] Signed-off-by: Weiping Zhang Signed-off-by: Martin K. Petersen --- Documentation/scsi/sd-parameters.txt | 22 ++++++++++++++++++++++ 1 file changed, 22 insertions(+) create mode 100644 Documentation/scsi/sd-parameters.txt (limited to 'Documentation/scsi') diff --git a/Documentation/scsi/sd-parameters.txt b/Documentation/scsi/sd-parameters.txt new file mode 100644 index 000000000000..8e5af00d88e7 --- /dev/null +++ b/Documentation/scsi/sd-parameters.txt @@ -0,0 +1,22 @@ +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 -- cgit