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 [options] [-o offset] [-l length] 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,
27       EiB, ZiB and YiB (the "iB" is optional, e.g., "K" has the same meaning
28       as "KiB") or the suffixes KB (=1000), MB (=1000*1000), and so on for
29       GB, TB, PB, EB, ZB and YB.
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31       -f, --force
32           Disable all checking. Since v2.36 the block device is open in
33           exclusive mode (O_EXCL) by default to avoid collision with mounted
34           filesystem or another kernel subsystem. The --force option disables
35           the exclusive access mode.
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37       -o, --offset offset
38           Byte offset into the device from which to start discarding. The
39           provided value must be aligned to the device sector size. The
40           default value is zero.
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42       -l, --length length
43           The number of bytes to discard (counting from the starting point).
44           The provided value must be aligned to the device sector size. If
45           the specified value extends past the end of the device, blkdiscard
46           will stop at the device size boundary. The default value extends to
47           the end of the device.
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49       -p, --step length
50           The number of bytes to discard within one iteration. The default is
51           to discard all by one ioctl call.
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53       -s, --secure
54           Perform a secure discard. A secure discard is the same as a regular
55           discard except that all copies of the discarded blocks that were
56           possibly created by garbage collection must also be erased. This
57           requires support from the device.
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59       -z, --zeroout
60           Zero-fill rather than discard.
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62       -v, --verbose
63           Display the aligned values of offset and length. If the --step
64           option is specified, it prints the discard progress every second.
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66       -h, --help
67           Display help text and exit.
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69       -V, --version
70           Print version and exit.
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AUTHORS

73       Lukas Czerner <lczerner@redhat.com>
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SEE ALSO

76       fstrim(8)
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REPORTING BUGS

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

83       The blkdiscard command is part of the util-linux package which can be
84       downloaded from Linux Kernel Archive
85       <https://www.kernel.org/pub/linux/utils/util-linux/>.
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89util-linux 2.38.1                 2022-05-11                     BLKDISCARD(8)
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