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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | AUTHOR | SEE ALSO | AVAILABILITY | COLOPHON |
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.
-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.
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
2017-07-05. If you discover any rendering problems in this HTML ver‐
sion 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 man‐
ual page), send a mail to man-pages@man7.org
util-linux July 2014 BLKDISCARD(8)
Pages that refer to this page: fstrim(8)