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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
40 .Cd "options GEOM_UZIP"
43 Alternatively, to load the driver as a
44 module at boot time, place the following line in
46 .Bd -literal -offset indent
52 framework provides support for compressed read-only
54 This allows significant storage savings at the expense of
55 a some CPU time on each read.
56 Data written in the GEOM label area allows
58 to detect compressed images which have been created with
60 and presented to the kernel as a logical disk device via
65 device for each image.
68 is not limited to supporting only
71 The image can also reside on a block device.
72 .Pq For example, a disk, USB flash drive, DVD-ROM, etc.
73 The appropriate device node will appear with the
76 .Bd -literal -offset indent
78 => 0 7833600 da0 BSD (3.7G)
79 0 2097152 1 freebsd-ufs (1.0G)
80 2097152 5736448 - free - (2.7G)
81 # gpart add -t freebsd-ufs -s 1G da0
83 # dd if=/tmp/20160217_dcomp_zcomp.uzip bs=256k of=/dev/da0b
86 836331008 bytes transferred in 111.021489 secs (7533055 bytes/sec)
87 # fsck -t ffs /dev/da0b.uzip
88 ** /dev/da0b.uzip (NO WRITE)
89 ** Last Mounted on /mnt
90 ** Phase 1 - Check Blocks and Sizes
91 ** Phase 2 - Check Pathnames
92 ** Phase 3 - Check Connectivity
93 ** Phase 4 - Check Reference Counts
94 ** Phase 5 - Check Cyl groups
95 97455 files, 604242 used, 184741 free (2349 frags, 22799 blocks,
97 # mount -o ro /dev/da0b.uzip /mnt
99 Filesystem 1K-blocks Used Avail Capacity Mounted on
100 /dev/da0b.uzip 3155932 2416968 738964 77% /mnt
105 device is subsequently used by
107 kernel to access the uncompressed data.
110 driver does not allow write operations to the underlying disk image.
116 .Bd -literal -offset indent
121 Mediasize: 22003712 (21M)
125 Mediasize: 9563648 (9.1M)
131 Mediasize: 3355443200 (3.1G)
135 Mediasize: 1073741824 (1.0G)
140 allows mounting the root file system from a compressed disk partition by
142 .Dv vfs.root.mountfrom
148 Several flags are provided for tracing
150 I/O operations and TOC parsing via the following sysctls.
151 .Bl -tag -width indent
152 .It Va kern.geom.uzip.debug
154 Zero disables logging.
155 Higher values enable more verbose debug logging for
157 Supported levels are from 0 (no logging) to 4 (maximum amount of logging).
158 .It Va kern.geom.uzip.debug_block
159 Log operations involving compressed cluster number.
170 driver was written by
171 .An Max Khon Aq Mt fjoe@FreeBSD.org .
172 The block de-duplication code as well as some
174 driver optimizations have been contributed by
175 .An Maxim Sobolev Aq Mt sobomax@FreeBSD.org .
176 The LZMA decompression support and CLOOP 3.0 support have been added by
177 .An Aleksandr Rybalko Aq Mt ray@FreeBSD.org .
179 This manual page was written by
180 .An Ceri Davies Aq Mt ceri@FreeBSD.org .