3 058b0118 2005-01-03 devnull vac \- create a vac archive on Venti
4 058b0118 2005-01-03 devnull .SH SYNOPSIS
10 058b0118 2005-01-03 devnull .I blocksize
13 058b0118 2005-01-03 devnull .I oldvacfile
16 058b0118 2005-01-03 devnull .I exclude
19 058b0118 2005-01-03 devnull .I vacfile
27 058b0118 2005-01-03 devnull .I file ...
28 058b0118 2005-01-03 devnull .SH DESCRIPTION
30 058b0118 2005-01-03 devnull creates an archival copy of Plan 9 file trees on Venti. It can be used
31 058b0118 2005-01-03 devnull to build a simple backup system. One of the unusual properties of Venti is
32 058b0118 2005-01-03 devnull that duplicate blocks are detected and coalesced. When
34 058b0118 2005-01-03 devnull is used on a file tree that shares data with an existing archive, the consumption of
35 058b0118 2005-01-03 devnull storage will be approximately equal to an incremental backup.
36 058b0118 2005-01-03 devnull This reduction in storage consumption occurs transparently to the user.
38 058b0118 2005-01-03 devnull As an optimization, the
42 058b0118 2005-01-03 devnull options, described below, can be used to explicitly create an archive relative to an existing archive.
43 058b0118 2005-01-03 devnull These options do not change the resulting archive generated by
44 058b0118 2005-01-03 devnull .IR vac ,
45 058b0118 2005-01-03 devnull but simply reduce the number of write operations to Venti.
47 058b0118 2005-01-03 devnull The output of
49 058b0118 2005-01-03 devnull is the hexadecimal representation of the Sha1 fingerprint of the root of the archive, in this format:
52 058b0118 2005-01-03 devnull vac:64daefaecc4df4b5cb48a368b361ef56012a4f46
55 058b0118 2005-01-03 devnull Option to
59 058b0118 2005-01-03 devnull .BI -b " blocksize
60 058b0118 2005-01-03 devnull Specifies the block size that data will be broken into.
61 058b0118 2005-01-03 devnull The units for the size can be specified by appending
63 058b0118 2005-01-03 devnull to indicate kilobytes.
64 058b0118 2005-01-03 devnull The default is 8k.
65 058b0118 2005-01-03 devnull The size must be in the range
66 058b0118 2005-01-03 devnull of 512 bytes to 52k.
68 058b0118 2005-01-03 devnull .BI -d " oldvacfile
69 058b0118 2005-01-03 devnull Reduce the number of blocks written to Venti by comparing the files to be stored with
70 058b0118 2005-01-03 devnull the contents of an existing
72 058b0118 2005-01-03 devnull file tree given by
73 058b0118 2005-01-03 devnull .IR oldvacfile .
75 058b0118 2005-01-03 devnull .BI -e " exclude
76 058b0118 2005-01-03 devnull Do not include the file or directory specified by
77 058b0118 2005-01-03 devnull .IR exclude .
78 058b0118 2005-01-03 devnull This option may be repeated multiple times.
80 058b0118 2005-01-03 devnull .BI -f " vacfile
81 058b0118 2005-01-03 devnull The results of
83 058b0118 2005-01-03 devnull are place in
84 058b0118 2005-01-03 devnull .IR vacfile ,
85 058b0118 2005-01-03 devnull or the standard output if no file is given.
87 058b0118 2005-01-03 devnull .BI -i " name
88 058b0118 2005-01-03 devnull Include standard input as one of the input files, storing it in the archive
89 058b0118 2005-01-03 devnull with the specified
90 058b0118 2005-01-03 devnull .IR name .
92 058b0118 2005-01-03 devnull .BI -h " host
93 058b0118 2005-01-03 devnull The network address of the Venti server.
94 058b0118 2005-01-03 devnull The default is taken from the environment variable
95 058b0118 2005-01-03 devnull .BR venti .
96 058b0118 2005-01-03 devnull .\" If this variable does not exist, then the default is the
97 058b0118 2005-01-03 devnull .\" metaname
98 058b0118 2005-01-03 devnull .\" .BR $venti ,
99 058b0118 2005-01-03 devnull .\" which can be configured via
100 058b0118 2005-01-03 devnull .\" .IR ndb (6).
103 058b0118 2005-01-03 devnull Expand and merge any
105 058b0118 2005-01-03 devnull archives that are found while reading the input files. This option is
106 058b0118 2005-01-03 devnull useful for building an archive from a collection of existing archives. Each archive is inserted
107 058b0118 2005-01-03 devnull into the new archive as if it had been unpacked in the directory in which it was found. Multiple
108 058b0118 2005-01-03 devnull archives can be unpacked in a single directory and the contents will be merged. To be detected, the
109 058b0118 2005-01-03 devnull archives must end in
110 058b0118 2005-01-03 devnull .LR .vac .
111 058b0118 2005-01-03 devnull Note, an archive is inserted by simply copying the root fingerprint and does not require
112 058b0118 2005-01-03 devnull the archive to be unpacked.
115 058b0118 2005-01-03 devnull Increase the performance of the
117 058b0118 2005-01-03 devnull option by detecting unchanged files based on a match of the files name and other meta data,
118 058b0118 2005-01-03 devnull rather than examining the contents of the files.
121 058b0118 2005-01-03 devnull Print out various statistics on standard error.
124 058b0118 2005-01-03 devnull Produce more verbose output on standard error, including the name of the files added to the archive
125 058b0118 2005-01-03 devnull and the vac archives that are expanded and merged.
126 058b0118 2005-01-03 devnull .SH SOURCE
127 c3674de4 2005-01-11 devnull .B \*9/src/cmd/vac
128 058b0118 2005-01-03 devnull .SH "SEE ALSO"
129 058b0118 2005-01-03 devnull Plan 9's \fIvacfs\fR(4) and \fIventi\fR(8)
