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.

       -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.

AUTHOR

       Lukas Czerner ⟨lczerner@redhat.com⟩

SEE ALSO

       fstrim(8)

AVAILABILITY

       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/⟩.