Venti is a SHA1-addressed block storage server.
for a full introduction.
Read reads a block with the given
score and numeric
type from the server
host and prints the block to standard output.
-h option is omitted,
read consults the environment variable
$venti for the name of the Venti server.
-t option is omitted,
read will try each type, one at a time, until it finds
one that works.
It prints the corresponding
-t command to standard error
to indicate the type of the block.
Write writes at most 56 kilobytes of data from standard input
to the server
host and prints the resulting score to standard output.
-t option is omitted,
write uses type 0,
denoting a data block.
-z option is given,
write zero truncates the block before writing it to the server.
score to be the score of a
It copies the entire tree of blocks reachable from
the root block from the server
srchost to the server
Ventis blocks are arranged in a directed acyclic graph (see venti(6));
there may be multiple paths from a root score to an
interior block (for example, if the same file contents are stored
under multiple names in an archive).
Copy runs more efficiently if it does not copy blocks
(and all their children) multiple times.
-f option causes
copy to assume that if a block already exists on the destination
Venti server, all its children also exist and need not be considered.
-m option causes
copy to maintain an in-memory list of blocks it has copied
and avoid considering the same block multiple times.
-f option is only useful if the destination Venti server is
known not to have lost any blocks due to disk corruption
or other failures.
-m option is only useful if enough memory is available to
hold the block list, which typically requires about 1%
of the total number of bytes being copied.
-r options control
copys reaction to errors reading
Copy always prints information to standard error
about each read error.
copy exits after printing the first error.
-i option is given, read errors are ignored.
This is dangerous behavior because it breaks the
assumption made by fast mode.
-r option is given,
copy replaces pointers to unreadable blocks with
pointers to the zero block.
It writes the new root score to standard output.
-v option prints scores as it copies them, total writes, and other
-V option prints debugging information about the Venti protocol