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GEOM_UNCOMPRESS(4)     FreeBSD Kernel Interfaces Manual	    GEOM_UNCOMPRESS(4)

NAME
     geom_uncompress --	GEOM based compressed disk images

SYNOPSIS
     To	compile	this driver into the kernel, place the following line in your
     kernel configuration file:

	   options GEOM_UNCOMPRESS

     Alternatively, to load the	driver as a module at boot time, place the
     following line in loader.conf(5):

	   geom_uncompress_load="YES"

DESCRIPTION
     The geom_uncompress framework provides support for	compressed read	only
     disk images.  This	allows significant storage savings at the expense of a
     little CPU	time on	each read.  Data written in the	GEOM label area	allows
     geom_uncompress to	detect compressed images which have been created with
     mkulzma(8)	or mkuzip(8) and presented to the kernel as a logical disk
     device via	md(4).	geom_uncompress	creates	a unique md#.uncompress	device
     for each image.

     The geom_uncompress device	is subsequently	used by	the FreeBSD kernel to
     access the	disk images.  The geom_uncompress driver does not allow	write
     operations	to the underlying disk image.  To check	which md(4) devices
     match a given geom_uncompress device:

	   # geom uncompress list
	   Geom	name: md0.uncompress
	   Providers:
	   1. Name: md0.uncompress
	      Mediasize: 52428800 (50M)
	      Sectorsize: 512
	      Mode: r1w0e0
	   Consumers:
	   1. Name: md0
	      Mediasize: 20864000 (20M)
	      Sectorsize: 512
	      Mode: r1w0e0

SEE ALSO
     GEOM(4), md(4), geom(8), mkulzma(8), mkuzip(8)

AUTHORS
     The geom_uncompress driver	was written by Maxim Sobolev
     <sobomax@FreeBSD.org> and Aleksandr Rybalko <ray@FreeBSD.org>.  This man-
     ual page was written by Luiz Otavio O Souza <loos@FreeBSD.org>.

FreeBSD	10.3			January	9, 2014			  FreeBSD 10.3

NAME | SYNOPSIS | DESCRIPTION | SEE ALSO | AUTHORS

Want to link to this manual page? Use this URL:
<https://www.freebsd.org/cgi/man.cgi?query=geom_uncompress&sektion=4&manpath=FreeBSD+10.3-RELEASE+and+Ports>

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