blkdiscard - discard sectors on a device
[options] [-o offset
] [-l length
is used to discard device sectors. This is useful for
solid-state drivers (SSDs) and thinly-provisioned storage. Unlike
, this command is used directly on the block device.
By default, blkdiscard
will discard all blocks on the device. Options may
be used to modify this behavior based on range or size, as explained below.
argument is the pathname of the block device.
WARNING: All data in the discarded region on the device will be lost!
arguments may be followed by the
multiplicative suffixes KiB (=1024), MiB (=1024*1024), and so on for GiB, TiB,
PiB, EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has
the same meaning as "KiB") or the suffixes KB (=1000), MB
(=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
- -o, --offset offset
- Byte offset into the device from which to start discarding.
The provided value will be aligned to the device sector size. The default
value is zero.
- -l, --length length
- The number of bytes to discard (counting from the starting
point). The provided value will be aligned to the device sector size. If
the specified value extends past the end of the device, blkdiscard
will stop at the device size boundary. The default value extends to the
end of the device.
- -p, --step length
- The number of bytes to discard within one iteration. The
default is to discard all by one ioctl call.
- -s, --secure
- Perform a secure discard. A secure discard is the same as a
regular discard except that all copies of the discarded blocks that were
possibly created by garbage collection must also be erased. This requires
support from the device.
- -z, --zeroout
- Zero-fill rather than discard.
- -v, --verbose
- Display the aligned values of offset and
length. If the --step option is specified, it prints the
discard progress every second.
- -V, --version
- Display version information and exit.
- -h, --help
- Display help text and exit.
The blkdiscard command is part of the util-linux package and is available