diff options
Diffstat (limited to 'share/man/man4/geom_uncompress.4')
-rw-r--r-- | share/man/man4/geom_uncompress.4 | 107 |
1 files changed, 107 insertions, 0 deletions
diff --git a/share/man/man4/geom_uncompress.4 b/share/man/man4/geom_uncompress.4 new file mode 100644 index 0000000..6e848d4 --- /dev/null +++ b/share/man/man4/geom_uncompress.4 @@ -0,0 +1,107 @@ +.\" Copyright (c) 2014, Luiz Otavio O Souza <loos@FreeBSD.org> +.\" All rights reserved. +.\" +.\" Redistribution and use in source and binary forms, with or without +.\" modification, are permitted provided that the following conditions +.\" are met: +.\" 1. Redistributions of source code must retain the above copyright +.\" notice, this list of conditions and the following disclaimer. +.\" 2. Redistributions in binary form must reproduce the above copyright +.\" notice, this list of conditions and the following disclaimer in the +.\" documentation and/or other materials provided with the distribution. +.\" +.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND +.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE +.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE +.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE +.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL +.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS +.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) +.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT +.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY +.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF +.\" SUCH DAMAGE. +.\" +.\" $FreeBSD$ +.\" +.Dd January 9, 2014 +.Dt GEOM_UNCOMPRESS 4 +.Os +.Sh NAME +.Nm geom_uncompress +.Nd "GEOM based compressed disk images" +.Sh SYNOPSIS +To compile this driver into the kernel, place the following line in your +kernel configuration file: +.Bd -ragged -offset indent +.Cd "options GEOM_UNCOMPRESS" +.Ed +.Pp +Alternatively, to load the driver as a module at boot time, place the +following line in +.Xr loader.conf 5 : +.Bd -literal -offset indent +geom_uncompress_load="YES" +.Ed +.Sh DESCRIPTION +The +.Nm +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 +.Nm +to detect compressed images which have been created with +.Xr mkulzma 8 +or +.Xr mkuzip 8 +and presented to the kernel as a logical disk device via +.Xr md 4 . +.Nm +creates a unique +.Pa md#.uncompress +device for each image. +.Pp +The +.Nm +device is subsequently used by the +.Fx +kernel to access the disk images. +The +.Nm +driver does not allow write operations to the underlying disk image. +To check which +.Xr md 4 +devices match a given +.Nm +device: +.Bd -literal -offset indent +# 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 +.Ed +.Sh SEE ALSO +.Xr GEOM 4 , +.Xr md 4 , +.Xr geom 8 , +.Xr mkulzma 8 , +.Xr mkuzip 8 +.Sh AUTHORS +.An -nosplit +The +.Nm +driver was written by +.An "Maxim Sobolev" Aq sobomax@FreeBSD.org +and +.An "Aleksandr Rybalko" Aq ray@FreeBSD.org . +This manual page was written by +.An "Luiz Otavio O Souza" Aq loos@FreeBSD.org . |