157 lines
3.8 KiB
HTML
157 lines
3.8 KiB
HTML
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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
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<HTML><HEAD><TITLE>Man page of BLKDISCARD</TITLE>
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</HEAD><BODY>
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<H1>BLKDISCARD</H1>
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Section: System Administration (8)<BR>Updated: July 2014<BR><A HREF="#index">Index</A>
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<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
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<A NAME="lbAB"> </A>
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<H2>NAME</H2>
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blkdiscard - discard sectors on a device
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<A NAME="lbAC"> </A>
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<H2>SYNOPSIS</H2>
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<B>blkdiscard</B>
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[options]
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[<B>-o</B>
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<I>offset</I>]
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[<B>-l</B>
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<I>length</I>]
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<I>device</I>
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<A NAME="lbAD"> </A>
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<H2>DESCRIPTION</H2>
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<B>blkdiscard</B>
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is used to discard device sectors. This is useful for solid-state
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drivers (SSDs) and thinly-provisioned storage. Unlike
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<B><A HREF="/cgi-bin/man/man2html?8+fstrim">fstrim</A></B>(8),
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this command is used directly on the block device.
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<P>
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By default,
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<B>blkdiscard</B>
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will discard all blocks on the device. Options may be used to modify
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this behavior based on range or size, as explained below.
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<P>
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The
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<I>device</I>
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argument is the pathname of the block device.
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<P>
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<B>WARNING: All data in the discarded region on the device will be lost!</B>
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<A NAME="lbAE"> </A>
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<H2>OPTIONS</H2>
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The
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<I>offset</I>
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and
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<I>length</I>
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arguments may be followed by the multiplicative suffixes KiB (=1024),
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MiB (=1024*1024), and so on for GiB, TiB, PiB, EiB, ZiB and YiB (the "iB" is
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optional, e.g., "K" has the same meaning as "KiB") or the suffixes
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KB (=1000), MB (=1000*1000), and so on for GB, TB, PB, EB, ZB and YB.
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<DL COMPACT>
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<DT id="1"><B>-o</B>,<B> --offset </B><I>offset</I>
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<DD>
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Byte offset into the device from which to start discarding. The provided value
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will be aligned to the device sector size. The default value is zero.
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<DT id="2"><B>-l</B>,<B> --length </B><I>length</I>
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<DD>
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The number of bytes to discard (counting from the starting point). The provided value
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will be aligned to the device sector size. If the specified value extends past
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the end of the device,
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<B>blkdiscard</B>
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will stop at the device size boundary. The default value extends to the end
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of the device.
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<DT id="3"><B>-p</B>,<B> --step </B><I>length</I>
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<DD>
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The number of bytes to discard within one iteration. The default is to discard
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all by one ioctl call.
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<DT id="4"><B>-s</B>,<B> --secure</B>
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<DD>
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Perform a secure discard. A secure discard is the same as a regular discard
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except that all copies of the discarded blocks that were possibly created by
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garbage collection must also be erased. This requires support from the device.
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<DT id="5"><B>-z</B>,<B> --zeroout</B>
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<DD>
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Zero-fill rather than discard.
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<DT id="6"><B>-v</B>,<B> --verbose</B>
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<DD>
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Display the aligned values of
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<I>offset</I>
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and
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<I>length</I>.
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If the <B>--step</B> option is specified, it prints the discard progress every second.
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<DT id="7"><B>-V</B>,<B> --version</B>
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<DD>
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Display version information and exit.
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<DT id="8"><B>-h</B>,<B> --help</B>
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<DD>
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Display help text and exit.
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</DL>
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<A NAME="lbAF"> </A>
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<H2>AUTHOR</H2>
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Lukas Czerner
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<A NAME="lbAG"> </A>
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<H2>SEE ALSO</H2>
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<B><A HREF="/cgi-bin/man/man2html?8+fstrim">fstrim</A></B>(8)
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<A NAME="lbAH"> </A>
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<H2>AVAILABILITY</H2>
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The blkdiscard command is part of the util-linux package and is available
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Linux Kernel Archive
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<P>
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<HR>
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<A NAME="index"> </A><H2>Index</H2>
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<DL>
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<DT id="9"><A HREF="#lbAB">NAME</A><DD>
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<DT id="10"><A HREF="#lbAC">SYNOPSIS</A><DD>
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<DT id="11"><A HREF="#lbAD">DESCRIPTION</A><DD>
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<DT id="12"><A HREF="#lbAE">OPTIONS</A><DD>
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<DT id="13"><A HREF="#lbAF">AUTHOR</A><DD>
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<DT id="14"><A HREF="#lbAG">SEE ALSO</A><DD>
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<DT id="15"><A HREF="#lbAH">AVAILABILITY</A><DD>
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</DL>
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<HR>
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This document was created by
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<A HREF="/cgi-bin/man/man2html">man2html</A>,
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using the manual pages.<BR>
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Time: 00:06:11 GMT, March 31, 2021
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