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