The following commands are supported:
getcache
Get and display the cache enables for the specified device.
setcache none | r | w | rw [save]
Set the cache enables for the specified device. The enables are as follows:
none
Disable all caches on the disk.
r
Enable the read cache, and disable all other caches on the disk.
w
Enable the write cache, and disable all other caches on the disk.
rw
Enable both the read and write caches on the disk.
save
If specified, and the cache enables are savable, saves the cache enables in the disk's non-volatile parameter storage.
synccache [force]
Causes the cache on the disk to be synchronized, flushing all dirty write cache blocks to the media. If force is specified, the cache synchronization command will be issued even if the kernel does not believe that there are any dirty cache blocks in the disk's cache.
keeplabel [yes | no]
Specify to keep or drop the in-core disklabel on the last close of the disk device. (Keep if yes is specified, drop if no is specified.)
badsector flush | list | retry
Used for managing the kernel's bad sector list for
wd(4) devices. The software bad sector list is only maintained if the option “WD_SOFTBADSECT” was specified on kernel configuration.
flush
Clears the in kernel list of bad sectors.
list
Prints out the list of bad sector ranges recorded by the kernel.
retry
Flushes the in kernel list and then retries all of the previously recorded bad sectors, causing the list to self update. This option can only be used with character devices.
addwedge name startblk blkcnt ptype
Define a “wedge” on the specified disk starting at block number
startblk and spanning
blkcnt blocks. The wedge will have the volume name
name and the partition type
ptype. Valid choices for ptype would be
unused,
swap,
ffs,
lfs,
ext2fs,
cd9660,
ados,
hfs,
msdos,
filecore,
raidframe,
ccd,
appleufs,
ntfs, and
cgd.
The device name of the virtual block device assigned to the wedge will be displayed after the wedge has been successfully created. See
dk(4) for more information about disk wedges.
delwedge dk
Delete the wedge specified by its device name dk from the specified disk.
getwedgeinfo
Display information about the specified disk wedge.
listwedges
List all of the wedges configured on the specified disk.
strategy [name]
Get and set the disk I/O scheduler (buffer queue strategy) on the drive. If you do not provide a
name argument, the currently selected strategy will be shown. To set the bufq strategy, the
name argument must be specified.
name must be the name of one of the built-in kernel disk I/O schedulers. To get the list of supported schedulers, use the following command:
$ sysctl kern.bufq.strategies
Note: The
addwedge and
delwedge commands only modify the in-kernel representation of disks; for modifying information on the disks themselves, refer to
fdisk(8) or
gpt(8).