projects / thirdparty / util-linux.git / blame
| Commit | Line | Data |
|---|---|---|
| d964b669 LC |
1 | .\" -*- nroff -*- |
| 2 | .TH BLKDISCARD 8 "September 2012" "util-linux" "System Administration" | |
| 3 | .SH NAME | |
| 4 | blkdiscard \- discard sectors on a device | |
| 5 | .SH SYNOPSIS | |
| 6 | .B blkdiscard | |
| 7 | .RB [ \-o | |
| 8 | .IR offset ] | |
| 9 | .RB [ \-l | |
| 10 | .IR length ] | |
| 11 | .RB [ \-s ] | |
| 12 | .RB [ \-v ] | |
| 13 | .I device | |
| 14 | ||
| 15 | .SH DESCRIPTION | |
| 16 | .B blkdiscard | |
| 17 | is used to discard device sectors. This is useful for solid-state | |
| 18 | drivers (SSDs) and thinly-provisioned storage. Unlike | |
| 19 | .BR fstrim (8) | |
| 20 | this command is used directly on the block device. | |
| 21 | .PP | |
| 22 | By default, | |
| 23 | .B blkdiscard | |
| 24 | will discard all blocks on the device. Options may be used to | |
| 25 | modify this behavior based on range or size, as explained below. | |
| 26 | .PP | |
| 27 | The | |
| 28 | .I device | |
| 29 | argument is the pathname of the block device. | |
| 30 | ||
| 31 | .B WARNING: All data in the discarded region on the device will be lost! | |
| 32 | ||
| 33 | .SH OPTIONS | |
| 34 | The \fIoffset\fR and \fIlength\fR arguments may be | |
| 35 | followed by the multiplicative suffixes KiB=1024, MiB=1024*1024, and so on for | |
| 36 | GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is optional, e.g. "K" has the same | |
| 37 | meaning as "KiB") or the suffixes KB=1000, MB=1000*1000, and so on for GB, PB, | |
| 38 | EB, ZB and YB. | |
| 39 | .IP "\fB\-h, \-\-help\fP" | |
| 40 | Print help and exit. | |
| 41 | .IP "\fB\-o, \-\-offset\fP \fIoffset\fP" | |
| 42 | Byte offset in the device from which to discard. Provided value will be | |
| 43 | aligned to the device sector size. Default value is zero. | |
| 44 | .IP "\fB\-l, \-\-length\fP \fIlength\fP" | |
| 45 | Number of bytes after starting point to discard. Provided value will be | |
| 46 | aligned to the device sector size. If the specified value extends past the | |
| 47 | end of the device, | |
| 48 | .B blkdiscard | |
| 49 | will stop at the device size boundary. Default value extends to the end | |
| 50 | of the device. | |
| 51 | .IP "\fB\-s, \-\-secure\fP" | |
| 52 | Perform secure discard. Secure discard is the same as regular discard except | |
| 53 | all copies of the discarded blocks possibly created by garbage collection must | |
| 54 | also be erased. It has to be supported by the device. | |
| 55 | .IP "\fB\-v, \-\-verbose\fP" | |
| 56 | Print aligned \fIoffset\fR and \fIlength\fR arguments. | |
| 57 | ||
| 58 | .SH AUTHOR | |
| 59 | .nf | |
| 60 | Lukas Czerner <lczerner@redhat.com> | |
| 61 | .fi | |
| 62 | .SH SEE ALSO | |
| 63 | .BR fstrim (8) | |
| 64 | .SH AVAILABILITY | |
| 65 | The blkdiscard command is part of the util-linux package and is available | |
| 66 | from ftp://ftp.kernel.org/pub/linux/utils/util-linux/. |