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.

       -h, --help
           Display help text and exit.

       -V, --version
           Print version and exit.

AUTHORS

       Lukas Czerner <lczerner@redhat.com>

SEE ALSO

       fstrim(8)

REPORTING BUGS

       For bug reports, use the issue tracker at https://github.com/util-linux/util-linux/issues.

AVAILABILITY

       The blkdiscard command is part of the util-linux package which can be downloaded from
       Linux Kernel Archive <https://www.kernel.org/pub/linux/utils/util-linux/>.