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33 .Nd "GEOM based compressed disk images and partitions"
35 To compile this driver into the kernel,
36 place the following line in your
37 kernel configuration file:
38 .Bd -ragged -offset indent
39 .Cd "options GEOM_UZIP"
42 Alternatively, to load the driver as a
43 module at boot time, place the following line in
45 .Bd -literal -offset indent
51 framework provides support for compressed read-only
53 This allows significant storage savings at the expense of
54 a some CPU time on each read.
55 Data written in the GEOM label area allows
57 to detect compressed images which have been created with
59 and presented to the kernel as a logical disk device via
64 device for each image.
67 is not limited to supporting only
70 The image can also reside on a block device.
71 .Pq For example, a disk, USB flash drive, DVD-ROM, etc.
72 The appropriate device node will appear with the
75 .Bd -literal -offset indent
77 => 0 7833600 da0 BSD (3.7G)
78 0 2097152 1 freebsd-ufs (1.0G)
79 2097152 5736448 - free - (2.7G)
80 # gpart add -t freebsd-ufs -s 1G da0
82 # dd if=/tmp/20160217_dcomp_zcomp.uzip bs=256k of=/dev/da0b
85 836331008 bytes transferred in 111.021489 secs (7533055 bytes/sec)
86 # fsck -t ffs /dev/da0b.uzip
87 ** /dev/da0b.uzip (NO WRITE)
88 ** Last Mounted on /mnt
89 ** Phase 1 - Check Blocks and Sizes
90 ** Phase 2 - Check Pathnames
91 ** Phase 3 - Check Connectivity
92 ** Phase 4 - Check Reference Counts
93 ** Phase 5 - Check Cyl groups
94 97455 files, 604242 used, 184741 free (2349 frags, 22799 blocks,
96 # mount -o ro /dev/da0b.uzip /mnt
98 Filesystem 1K-blocks Used Avail Capacity Mounted on
99 /dev/da0b.uzip 3155932 2416968 738964 77% /mnt
104 device is subsequently used by
106 kernel to access the uncompressed data.
109 driver does not allow write operations to the underlying disk image.
115 .Bd -literal -offset indent
120 Mediasize: 22003712 (21M)
124 Mediasize: 9563648 (9.1M)
130 Mediasize: 3355443200 (3.1G)
134 Mediasize: 1073741824 (1.0G)
139 allows mounting the root file system from a compressed disk partition by
141 .Dv vfs.root.mountfrom
147 Several flags are provided for tracing
149 I/O operations and TOC parsing via the following sysctls.
150 .Bl -tag -width indent
151 .It Va kern.geom.uzip.debug
153 Zero disables logging.
154 Higher values enable more verbose debug logging for
156 Supported levels are from 0 (no logging) to 4 (maximum amount of logging).
157 .It Va kern.geom.uzip.debug_block
158 Log operations involving compressed cluster number.
169 driver was written by
170 .An Max Khon Aq Mt fjoe@FreeBSD.org .
171 The block de-duplication code as well as some
173 driver optimizations have been contributed by
174 .An Maxim Sobolev Aq Mt sobomax@FreeBSD.org .
175 The LZMA decompression support and CLOOP 3.0 support have been added by
176 .An Aleksandr Rybalko Aq Mt ray@FreeBSD.org .
178 This manual page was written by
179 .An Ceri Davies Aq Mt ceri@FreeBSD.org .