1BLKDISCARD(8)                System Administration               BLKDISCARD(8)
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NAME

6       blkdiscard - discard sectors on a device
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SYNOPSIS

9       blkdiscard [-o offset] [-l length] [-s] [-v] device
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DESCRIPTION

12       blkdiscard  is  used  to  discard  device  sectors.  This is useful for
13       solid-state drivers  (SSDs)  and  thinly-provisioned  storage.   Unlike
14       fstrim(8) this command is used directly on the block device.
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16       By  default, blkdiscard will discard all blocks on the device.  Options
17       may be used to  modify  this  behavior  based  on  range  or  size,  as
18       explained below.
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20       The device argument is the pathname of the block device.
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22       WARNING: All data in the discarded region on the device will be lost!
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OPTIONS

25       The  offset  and length arguments may be followed by the multiplicative
26       suffixes KiB=1024, MiB=1024*1024, and so on for GiB, TiB, PiB, EiB, ZiB
27       and YiB (the "iB" is optional, e.g., "K" has the same meaning as "KiB")
28       or the suffixes KB=1000, MB=1000*1000, and so on for GB, TB, PB, EB, ZB
29       and YB.
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31       -h, --help
32              Print help and exit.
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34       -o, --offset offset
35              Byte offset in the device from which to discard.  Provided value
36              will be aligned to the device sector  size.   Default  value  is
37              zero.
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39       -l, --length length
40              Number of bytes after starting point to discard.  Provided value
41              will be aligned to the device sector  size.   If  the  specified
42              value  extends  past the end of the device, blkdiscard will stop
43              at the device size boundary.  Default value extends to  the  end
44              of the device.
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46       -s, --secure
47              Perform  secure  discard.  Secure discard is the same as regular
48              discard except all copies of the discarded blocks possibly  cre‐
49              ated  by  garbage  collection must also be erased.  It has to be
50              supported by the device.
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52       -v, --verbose
53              Print aligned offset and length arguments.
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AUTHOR

56       Lukas Czerner ⟨lczerner@redhat.com⟩
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SEE ALSO

59       fstrim(8)
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AVAILABILITY

62       The blkdiscard command is part of the util-linux package and is  avail‐
63       able  Linux  Kernel Archive ⟨ftp://ftp.kernel.org/pub/linux/utils/util-
64       linux/⟩.
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68util-linux                       October 2012                    BLKDISCARD(8)
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