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+.TH BLKDISCARD 8 "July 2014" "util-linux" "System Administration"
+.SH NAME
+blkdiscard \- discard sectors on a device
+.SH SYNOPSIS
+.B blkdiscard
+[options]
+.RB [ \-o
+.IR offset ]
+.RB [ \-l
+.IR length ]
+.I device
+.SH DESCRIPTION
+.B blkdiscard
+is used to discard device sectors.  This is useful for solid-state
+drivers (SSDs) and thinly-provisioned storage.  Unlike
+.BR fstrim (8),
+this command is used directly on the block device.
+.PP
+By default,
+.B blkdiscard
+will discard all blocks on the device.  Options may be used to modify
+this behavior based on range or size, as explained below.
+.PP
+The
+.I device
+argument is the pathname of the block device.
+.PP
+.B WARNING: All data in the discarded region on the device will be lost!
+.SH OPTIONS
+The
+.I offset
+and
+.I 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.
+.TP
+.BR \-o , " \-\-offset \fIoffset"
+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.
+.TP
+.BR \-l , " \-\-length \fIlength"
+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,
+.B blkdiscard
+will stop at the device size boundary.  The default value extends to the end
+of the device.
+.TP
+.BR \-p , " \-\-step \fIlength"
+The number of bytes to discard within one iteration. The default is to discard
+all by one ioctl call.
+.TP
+.BR \-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.
+.TP
+.BR \-z , " \-\-zeroout"
+Zero-fill rather than discard.
+.TP
+.BR \-v , " \-\-verbose"
+Display the aligned values of
+.I offset
+and
+.IR length .
+If the \fB\-\-step\fR option is specified, it prints the discard progress every second.
+.TP
+.BR \-V , " \-\-version"
+Display version information and exit.
+.TP
+.BR \-h , " \-\-help"
+Display help text and exit.
+.SH AUTHOR
+.MT lczerner@redhat.com
+Lukas Czerner
+.ME
+.SH SEE ALSO
+.BR fstrim (8)
+.SH AVAILABILITY
+The blkdiscard command is part of the util-linux package and is available
+.UR https://\:www.kernel.org\:/pub\:/linux\:/utils\:/util-linux/
+Linux Kernel Archive
+.UE .