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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
41 .Cd "options GEOM_UZIP"
44 Alternatively, to load the driver as a
45 module at boot time, place the following line in
47 .Bd -literal -offset indent
53 framework provides support for compressed read-only
55 This allows significant storage savings at the expense of
56 a some CPU time on each read.
57 Data written in the GEOM label area allows
59 to detect compressed images which have been created with
61 and presented to the kernel as a logical disk device via
66 device for each image.
69 is not limited to supporting only
72 The image can also reside on a block device.
73 .Pq For example, a disk, USB flash drive, DVD-ROM, etc.
74 The appropriate device node will appear with the
77 .Bd -literal -offset indent
79 => 0 7833600 da0 BSD (3.7G)
80 0 2097152 1 freebsd-ufs (1.0G)
81 2097152 5736448 - free - (2.7G)
82 # gpart add -t freebsd-ufs -s 1G da0
84 # dd if=/tmp/20160217_dcomp_zcomp.uzip bs=256k of=/dev/da0b
87 836331008 bytes transferred in 111.021489 secs (7533055 bytes/sec)
88 # fsck -t ffs /dev/da0b.uzip
89 ** /dev/da0b.uzip (NO WRITE)
90 ** Last Mounted on /mnt
91 ** Phase 1 - Check Blocks and Sizes
92 ** Phase 2 - Check Pathnames
93 ** Phase 3 - Check Connectivity
94 ** Phase 4 - Check Reference Counts
95 ** Phase 5 - Check Cyl groups
96 97455 files, 604242 used, 184741 free (2349 frags, 22799 blocks,
98 # mount -o ro /dev/da0b.uzip /mnt
100 Filesystem 1K-blocks Used Avail Capacity Mounted on
101 /dev/da0b.uzip 3155932 2416968 738964 77% /mnt
106 device is subsequently used by
108 kernel to access the uncompressed data.
111 driver does not allow write operations to the underlying disk image.
117 .Bd -literal -offset indent
122 Mediasize: 22003712 (21M)
126 Mediasize: 9563648 (9.1M)
132 Mediasize: 3355443200 (3.1G)
136 Mediasize: 1073741824 (1.0G)
141 allows mounting the root file system from a compressed disk partition by
143 .Dv vfs.root.mountfrom
149 Several flags are provided for tracing
151 I/O operations and TOC parsing via the following sysctls.
152 .Bl -tag -width indent
153 .It Va kern.geom.uzip.debug
155 Zero disables logging.
156 Higher values enable more verbose debug logging for
158 Supported levels are from 0 (no logging) to 4 (maximum amount of logging).
159 .It Va kern.geom.uzip.debug_block
160 Log operations involving compressed cluster number.
168 Zstd support was added in
174 driver was written by
175 .An Max Khon Aq Mt fjoe@FreeBSD.org .
176 The block de-duplication code as well as some
178 driver optimizations have been contributed by
179 .An Maxim Sobolev Aq Mt sobomax@FreeBSD.org .
180 The LZMA decompression support and CLOOP 3.0 support have been added by
181 .An Aleksandr Rybalko Aq Mt ray@FreeBSD.org .
183 This manual page was written by
184 .An Ceri Davies Aq Mt ceri@FreeBSD.org .