blkdiscard(8) - phpMan

BLKDISCARD(8) System Administration BLKDISCARD(8)

NAME
blkdiscard - discard sectors on a device

SYNOPSIS
blkdiscard [options] [-o offset] [-l length] 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
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!

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.

-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.

AUTHORS
Lukas Czerner <lczerner AT redhat.com>