1 be7cbb4e 2005-07-12 devnull .TH VENTI 1
3 be7cbb4e 2005-07-12 devnull read, write, copy \- simple Venti clients
4 be7cbb4e 2005-07-12 devnull .SH SYNOPSIS
5 be7cbb4e 2005-07-12 devnull .B venti/read
16 be7cbb4e 2005-07-12 devnull .B venti/write
29 be7cbb4e 2005-07-12 devnull .B venti/copy
31 da0a205e 2009-08-21 extrudeda .B -fimrVv
37 be7cbb4e 2005-07-12 devnull .I srchost
38 be7cbb4e 2005-07-12 devnull .I dsthost
40 be7cbb4e 2005-07-12 devnull .SH DESCRIPTION
41 be7cbb4e 2005-07-12 devnull Venti is a SHA1-addressed block storage server.
43 be7cbb4e 2005-07-12 devnull .IR venti (7)
44 be7cbb4e 2005-07-12 devnull for a full introduction.
47 be7cbb4e 2005-07-12 devnull reads a block with the given
49 be7cbb4e 2005-07-12 devnull and numeric
51 be7cbb4e 2005-07-12 devnull from the server
53 be7cbb4e 2005-07-12 devnull and prints the block to standard output.
56 be7cbb4e 2005-07-12 devnull option is omitted,
58 be7cbb4e 2005-07-12 devnull consults the environment variable
59 be7cbb4e 2005-07-12 devnull .B $venti
60 be7cbb4e 2005-07-12 devnull for the name of the Venti server.
63 be7cbb4e 2005-07-12 devnull option is omitted,
65 be7cbb4e 2005-07-12 devnull will try each type, one at a time, until it finds
66 be7cbb4e 2005-07-12 devnull one that works.
67 be7cbb4e 2005-07-12 devnull It prints the corresponding
70 be7cbb4e 2005-07-12 devnull command to standard error
71 be7cbb4e 2005-07-12 devnull to indicate the type of the block.
74 be7cbb4e 2005-07-12 devnull writes at most 56 kilobytes of data from standard input
75 be7cbb4e 2005-07-12 devnull to the server
77 be7cbb4e 2005-07-12 devnull and prints the resulting score to standard output.
80 be7cbb4e 2005-07-12 devnull option is omitted,
82 be7cbb4e 2005-07-12 devnull uses type 0,
83 be7cbb4e 2005-07-12 devnull denoting a data block.
86 be7cbb4e 2005-07-12 devnull option is given,
88 3aec33fe 2005-07-18 devnull zero truncates the block before writing it to the server.
93 be7cbb4e 2005-07-12 devnull to be the score of a
94 be7cbb4e 2005-07-12 devnull .B VtRoot
96 be7cbb4e 2005-07-12 devnull It copies the entire tree of blocks reachable from
97 be7cbb4e 2005-07-12 devnull the root block from the server
98 be7cbb4e 2005-07-12 devnull .I srchost
99 be7cbb4e 2005-07-12 devnull to the server
100 be7cbb4e 2005-07-12 devnull .IR dsthost .
102 da0a205e 2009-08-21 extrudeda Venti's blocks are arranged in a directed acyclic graph (see venti(6));
103 da0a205e 2009-08-21 extrudeda there may be multiple paths from a root score to an
104 da0a205e 2009-08-21 extrudeda interior block (for example, if the same file contents are stored
105 da0a205e 2009-08-21 extrudeda under multiple names in an archive).
106 da0a205e 2009-08-21 extrudeda .I Copy
107 da0a205e 2009-08-21 extrudeda runs more efficiently if it does not copy blocks
108 da0a205e 2009-08-21 extrudeda (and all their children) multiple times.
111 be7cbb4e 2005-07-12 devnull option causes
113 da0a205e 2009-08-21 extrudeda to assume that if a block already exists on the destination
114 da0a205e 2009-08-21 extrudeda Venti server, all its children also exist and need not be considered.
117 da0a205e 2009-08-21 extrudeda option causes
118 da0a205e 2009-08-21 extrudeda .I copy
119 da0a205e 2009-08-21 extrudeda to maintain an in-memory list of blocks it has copied
120 da0a205e 2009-08-21 extrudeda and avoid considering the same block multiple times.
123 da0a205e 2009-08-21 extrudeda option is only useful if the destination Venti server is
124 da0a205e 2009-08-21 extrudeda known not to have lost any blocks due to disk corruption
125 da0a205e 2009-08-21 extrudeda or other failures.
128 da0a205e 2009-08-21 extrudeda option is only useful if enough memory is available to
129 da0a205e 2009-08-21 extrudeda hold the block list, which typically requires about 1%
130 da0a205e 2009-08-21 extrudeda of the total number of bytes being copied.
136 a7f1ab29 2011-05-10 rsc options control
137 be7cbb4e 2005-07-12 devnull .IR copy 's
138 3aec33fe 2005-07-18 devnull reaction to errors reading
140 3aec33fe 2005-07-18 devnull .IR srchost .
142 be7cbb4e 2005-07-12 devnull always prints information to standard error
143 be7cbb4e 2005-07-12 devnull about each read error.
144 be7cbb4e 2005-07-12 devnull By default,
146 3aec33fe 2005-07-18 devnull exits after printing the first error.
149 be7cbb4e 2005-07-12 devnull option is given, read errors are ignored.
150 be7cbb4e 2005-07-12 devnull This is dangerous behavior because it breaks the
151 be7cbb4e 2005-07-12 devnull assumption made by `fast' mode.
154 be7cbb4e 2005-07-12 devnull option is given,
156 be7cbb4e 2005-07-12 devnull replaces pointers to unreadable blocks with
157 be7cbb4e 2005-07-12 devnull pointers to the zero block.
158 be7cbb4e 2005-07-12 devnull It writes the new root score to standard output.
161 da0a205e 2009-08-21 extrudeda option prints scores as it copies them, total writes, and other
162 da0a205e 2009-08-21 extrudeda debugging information.
165 da0a205e 2009-08-21 extrudeda option prints debugging information about the Venti protocol
166 da0a205e 2009-08-21 extrudeda messages send/received.
167 be7cbb4e 2005-07-12 devnull .SH SOURCE
168 e5e159fd 2005-07-18 devnull .B \*9/src/cmd/venti
169 be7cbb4e 2005-07-12 devnull .SH SEE ALSO
170 be7cbb4e 2005-07-12 devnull .IR vac (1),
171 be7cbb4e 2005-07-12 devnull .IR venti (3),
172 be7cbb4e 2005-07-12 devnull .IR vacfs (4),
173 be7cbb4e 2005-07-12 devnull .IR venti (7),
174 3aec33fe 2005-07-18 devnull .IR vbackup (8),
175 cbc99e3e 2011-06-03 rsc .IR venti (8),
176 cbc99e3e 2011-06-03 rsc .IR venti-fmt (8)
177 be7cbb4e 2005-07-12 devnull .SH BUGS
178 be7cbb4e 2005-07-12 devnull There should be programs to read and write
179 3aec33fe 2005-07-18 devnull venti files and directories.