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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | AUTHORS | SEE ALSO | AVAILABILITY | COLOPHON |
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BLKDISCARD(8) System Administration BLKDISCARD(8)
blkdiscard - discard sectors on a device
blkdiscard [options] [-o offset] [-l length] device
blkdiscard is used to discard device sectors. This is useful for
solid-state drivers (SSDs) and thinly-provisioned storage.
Unlike fstrim(8), 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.
The device argument is the pathname of the block device.
WARNING: All data in the discarded region on the device will be
lost!
The offset and length 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.
-f, --force
Disable all checking. Since v2.36 the block device is
open in exclusive mode (O_EXCL) by default to avoid
collision with mounted filesystem or another kernel
subsystem. The force option disables the exclusive access
mode.
-o, --offset offset
Byte offset into the device from which to start
discarding. The provided value must 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 must 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.
Lukas Czerner ⟨lczerner@redhat.com⟩
fstrim(8)
The blkdiscard command is part of the util-linux package and is
available Linux Kernel Archive
⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩.
This page is part of the util-linux (a random collection of Linux
utilities) project. Information about the project can be found
at ⟨https://www.kernel.org/pub/linux/utils/util-linux/⟩. If you
have a bug report for this manual page, send it to
util-linux@vger.kernel.org. This page was obtained from the
project's upstream Git repository
⟨git://git.kernel.org/pub/scm/utils/util-linux/util-linux.git⟩ on
2020-12-18. (At that time, the date of the most recent commit
that was found in the repository was 2020-12-17.) If you
discover any rendering problems in this HTML version of the page,
or you believe there is a better or more up-to-date source for
the page, or you have corrections or improvements to the
information in this COLOPHON (which is not part of the original
manual page), send a mail to man-pages@man7.org
util-linux July 2014 BLKDISCARD(8)
Pages that refer to this page: fstrim(8)
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