| BLKDISCARD(8) - phpMan
BLKDISCARD(8) System Administration BLKDISCARD(8)
NAME
blkdiscard - discard sectors on a device
SYNOPSIS
blkdiscard [-o offset] [-l length] [-s] [-v] device
DESCRIPTION
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 mod‐
ify 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!
OPTIONS
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.
-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 col‐
lection must also be erased. This requires support from the device.
-v, --verbose
Display the aligned values of offset and length.
-V, --version
Display version information and exit.
-h, --help
Display help text and exit.
AUTHOR
Lukas Czerner ⟨lczerner AT redhat.com⟩
SEE ALSO
fstrim(8)
AVAILABILITY
The blkdiscard command is part of the util-linux package and is available Linux Kernel
Archive ⟨ftp://ftp.kernel.org/pub/linux/utils/util-linux/⟩.
util-linux July 2014 BLKDISCARD(8)
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