xref: /linux/Documentation/scsi/sd-parameters.rst (revision 702648721db590b3425c31ade294000e18808345)
1.. SPDX-License-Identifier: GPL-2.0
2
3======================================
4Linux SCSI Disk Driver (sd) Parameters
5======================================
6
7cache_type (RW)
8---------------
9Enable/disable drive write & read cache.
10
11===========================   === ===   ===========   ==========
12 cache_type string            WCE RCD   Write cache   Read cache
13===========================   === ===   ===========   ==========
14 write through                0   0     off           on
15 none                         0   1     off           off
16 write back                   1   0     on            on
17 write back, no read (daft)   1   1     on            off
18===========================   === ===   ===========   ==========
19
20To set cache type to "write back" and save this setting to the drive::
21
22  # echo "write back" > cache_type
23
24To modify the caching mode without making the change persistent, prepend
25"temporary " to the cache type string. E.g.::
26
27  # echo "temporary write back" > cache_type
28