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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-provi‐
       sioned 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 option --step specified than it prints discard
              progress every second.

       -V, --version
              Display version information and exit.

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

AUTHOR
       Lukas Czerner ⟨[email protected]⟩

SEE ALSO