3 405d555f 2008-06-14 rsc vac, unvac \- create, extract a vac archive on Venti
4 058b0118 2005-01-03 devnull .SH SYNOPSIS
13 058b0118 2005-01-03 devnull .I blocksize
16 058b0118 2005-01-03 devnull .I oldvacfile
19 058b0118 2005-01-03 devnull .I exclude
22 058b0118 2005-01-03 devnull .I vacfile
31 e05b0ff3 2008-07-03 rsc .I excludefile
33 058b0118 2005-01-03 devnull .I file ...
46 058b0118 2005-01-03 devnull .SH DESCRIPTION
48 058b0118 2005-01-03 devnull creates an archival copy of Plan 9 file trees on Venti. It can be used
49 058b0118 2005-01-03 devnull to build a simple backup system. One of the unusual properties of Venti is
50 058b0118 2005-01-03 devnull that duplicate blocks are detected and coalesced. When
52 058b0118 2005-01-03 devnull is used on a file tree that shares data with an existing archive, the consumption of
53 058b0118 2005-01-03 devnull storage will be approximately equal to an incremental backup.
54 058b0118 2005-01-03 devnull This reduction in storage consumption occurs transparently to the user.
56 977b25a7 2020-08-14 rsc As an optimization, the
60 058b0118 2005-01-03 devnull options, described below, can be used to explicitly create an archive relative to an existing archive.
61 058b0118 2005-01-03 devnull These options do not change the resulting archive generated by
62 058b0118 2005-01-03 devnull .IR vac ,
63 058b0118 2005-01-03 devnull but simply reduce the number of write operations to Venti.
65 058b0118 2005-01-03 devnull The output of
67 405d555f 2008-06-14 rsc is the hexadecimal representation of the SHA1 fingerprint of the root of the archive, in this format:
70 058b0118 2005-01-03 devnull vac:64daefaecc4df4b5cb48a368b361ef56012a4f46
73 405d555f 2008-06-14 rsc The options are:
75 e05b0ff3 2008-07-03 rsc .BI -a " vacfile
76 e05b0ff3 2008-07-03 rsc Specifies that vac should create or update a backup archive, inserting
77 e05b0ff3 2008-07-03 rsc the files under an extra two levels of directory hierarchy named
79 e05b0ff3 2008-07-03 rsc (year, month, day)
80 e05b0ff3 2008-07-03 rsc in the style of the dump file system
81 977b25a7 2020-08-14 rsc (see Plan 9's
85 e05b0ff3 2008-07-03 rsc already exists, an additional backup day is added to the
86 e05b0ff3 2008-07-03 rsc existing hierarchy, behaving as though the
88 e05b0ff3 2008-07-03 rsc flag was specified giving the most recent backup tree in the archive.
89 e05b0ff3 2008-07-03 rsc Typically, this option
90 e05b0ff3 2008-07-03 rsc is used as part of a nightly backup script.
91 e05b0ff3 2008-07-03 rsc This option cannot be used with
96 058b0118 2005-01-03 devnull .BI -b " blocksize
97 058b0118 2005-01-03 devnull Specifies the block size that data will be broken into.
98 058b0118 2005-01-03 devnull The units for the size can be specified by appending
100 058b0118 2005-01-03 devnull to indicate kilobytes.
101 058b0118 2005-01-03 devnull The default is 8k.
102 058b0118 2005-01-03 devnull The size must be in the range
103 058b0118 2005-01-03 devnull of 512 bytes to 52k.
105 058b0118 2005-01-03 devnull .BI -d " oldvacfile
106 058b0118 2005-01-03 devnull Reduce the number of blocks written to Venti by comparing the files to be stored with
107 058b0118 2005-01-03 devnull the contents of an existing
109 a7f1ab29 2011-05-10 rsc file tree whose score is stored in
110 058b0118 2005-01-03 devnull .IR oldvacfile .
112 058b0118 2005-01-03 devnull .BI -e " exclude
113 058b0118 2005-01-03 devnull Do not include the file or directory specified by
114 058b0118 2005-01-03 devnull .IR exclude .
115 058b0118 2005-01-03 devnull This option may be repeated multiple times.
117 e05b0ff3 2008-07-03 rsc can be a shell pattern as accepted by
118 d32deab1 2020-08-16 rsc .MR rc (1) ,
119 977b25a7 2020-08-14 rsc with one extension:
121 e05b0ff3 2008-07-03 rsc matches any sequence of characters including slashes.
123 058b0118 2005-01-03 devnull .BI -f " vacfile
124 977b25a7 2020-08-14 rsc The results of
126 a7f1ab29 2011-05-10 rsc are placed in
127 058b0118 2005-01-03 devnull .IR vacfile ,
128 058b0118 2005-01-03 devnull or the standard output if no file is given.
130 058b0118 2005-01-03 devnull .BI -i " name
131 058b0118 2005-01-03 devnull Include standard input as one of the input files, storing it in the archive
132 058b0118 2005-01-03 devnull with the specified
133 058b0118 2005-01-03 devnull .IR name .
135 058b0118 2005-01-03 devnull .BI -h " host
136 058b0118 2005-01-03 devnull The network address of the Venti server.
137 058b0118 2005-01-03 devnull The default is taken from the environment variable
138 058b0118 2005-01-03 devnull .BR venti .
139 058b0118 2005-01-03 devnull .\" If this variable does not exist, then the default is the
140 977b25a7 2020-08-14 rsc .\" metaname
141 058b0118 2005-01-03 devnull .\" .BR $venti ,
142 058b0118 2005-01-03 devnull .\" which can be configured via
143 058b0118 2005-01-03 devnull .\" .IR ndb (6).
146 058b0118 2005-01-03 devnull Expand and merge any
148 058b0118 2005-01-03 devnull archives that are found while reading the input files. This option is
149 058b0118 2005-01-03 devnull useful for building an archive from a collection of existing archives. Each archive is inserted
150 058b0118 2005-01-03 devnull into the new archive as if it had been unpacked in the directory in which it was found. Multiple
151 058b0118 2005-01-03 devnull archives can be unpacked in a single directory and the contents will be merged. To be detected, the
152 058b0118 2005-01-03 devnull archives must end in
153 058b0118 2005-01-03 devnull .LR .vac .
154 058b0118 2005-01-03 devnull Note, an archive is inserted by simply copying the root fingerprint and does not require
155 058b0118 2005-01-03 devnull the archive to be unpacked.
158 058b0118 2005-01-03 devnull Increase the performance of the
162 e05b0ff3 2008-07-03 rsc options by detecting unchanged files based on a match of the files name and other meta data,
163 058b0118 2005-01-03 devnull rather than examining the contents of the files.
166 058b0118 2005-01-03 devnull Print out various statistics on standard error.
169 058b0118 2005-01-03 devnull Produce more verbose output on standard error, including the name of the files added to the archive
170 058b0118 2005-01-03 devnull and the vac archives that are expanded and merged.
172 e05b0ff3 2008-07-03 rsc .BI -x " excfile
173 977b25a7 2020-08-14 rsc Read exclude patterns from the file
174 e05b0ff3 2008-07-03 rsc .IR excfile .
175 977b25a7 2020-08-14 rsc Blank lines and lines beginning with
177 e05b0ff3 2008-07-03 rsc are ignored.
178 e05b0ff3 2008-07-03 rsc All other lines should be of the form
183 e05b0ff3 2008-07-03 rsc .I pattern .
184 e05b0ff3 2008-07-03 rsc When considering whether to include a directory or file
185 e05b0ff3 2008-07-03 rsc in the vac archive,
186 e05b0ff3 2008-07-03 rsc the earliest matching pattern in the file
188 e05b0ff3 2008-07-03 rsc The patterns are the same syntax accepted by the
191 e05b0ff3 2008-07-03 rsc This option may be repeated multiple times.
194 405d555f 2008-06-14 rsc lists or extracts files stored in the vac archive
195 5f1eaee2 2008-06-14 rsc .IR vacfile ,
196 405d555f 2008-06-14 rsc which can be either a vac archive string in the format
197 405d555f 2008-06-14 rsc given above or the name of a file containing one.
200 405d555f 2008-06-14 rsc arguments are given, only those files or directories
201 405d555f 2008-06-14 rsc will be extracted.
202 405d555f 2008-06-14 rsc The options are:
205 405d555f 2008-06-14 rsc Set the modification time on extracted files
206 405d555f 2008-06-14 rsc to the time listed in the archive.
209 405d555f 2008-06-14 rsc Write extracted files to standard output instead of creating a file.
212 286bb40b 2008-12-07 rsc Reduce the number of blocks read from Venti by
213 286bb40b 2008-12-07 rsc comparing the files to be stored with their counterparts
214 286bb40b 2008-12-07 rsc in the file system.
215 286bb40b 2008-12-07 rsc This option cannot be used with
219 405d555f 2008-06-14 rsc Print a list of the files to standard output rather than extracting them.
222 405d555f 2008-06-14 rsc If extracting files, print the name of each file and directory
223 405d555f 2008-06-14 rsc to standard error.
224 405d555f 2008-06-14 rsc If listing files, print metadata in addition to the names.
225 058b0118 2005-01-03 devnull .SH SOURCE
226 c3674de4 2005-01-11 devnull .B \*9/src/cmd/vac
227 058b0118 2005-01-03 devnull .SH "SEE ALSO"
228 d32deab1 2020-08-16 rsc .MR vacfs (4) ,
229 d32deab1 2020-08-16 rsc .MR venti (8)
