various bug fixes
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14 changed files with 1236 additions and 9 deletions
148
man/man1/graph.1
Normal file
148
man/man1/graph.1
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.TH GRAPH 1
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.CT 1 numbers graphics
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.SH NAME
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graph \- draw a graph
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.SH SYNOPSIS
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.B graph
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[
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.I option ...
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]
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.SH DESCRIPTION
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.I Graph
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with no options takes pairs of numbers from the
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standard input as abscissas
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.RI ( x -values)
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and ordinates
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.RI ( y -values)
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of a graph.
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Successive points are connected by straight lines.
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The graph is encoded on the standard output
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for display by
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.IR plot (1)
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filters.
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.PP
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If an ordinate is followed by
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a nonnumeric string, that string is printed as a
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label beginning on the point.
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Labels may be surrounded with quotes
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.L
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" "
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in which case they may be empty or contain blanks
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and numbers;
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labels never contain newlines.
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.PP
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The following options are recognized,
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each as a separate argument.
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.TP
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.B -a
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Supply abscissas automatically; no
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.IR x -values
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appear in the input.
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Spacing is given by the next
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argument (default 1).
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A second optional argument is the starting point for
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automatic abscissas (default 0, or 1
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with a log scale in
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.IR x ,
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or the lower limit given by
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.BR -x ).
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.TP
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.B -b
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Break (disconnect) the graph after each label in the input.
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.TP
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.B -c
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Character string given by next argument
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is default label for each point.
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.TP
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.B -g
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Next argument is grid style,
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0 no grid, 1 frame with ticks, 2 full grid (default).
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.TP
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.B -l
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Next argument is a legend to title the graph.
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Grid ranges
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are automatically printed as part
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of the title unless a
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.B -s
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option is present.
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.TP
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.B -m
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Next argument is mode (style)
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of connecting lines:
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0 disconnected, 1 connected.
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Some devices give distinguishable line styles
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for other small integers.
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Mode \-1 (default) begins with style 1 and
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rotates styles for successive curves under option
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.BR -o .
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.TP
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.B -o
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(Overlay.)
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The ordinates for
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.I n
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superposed curves appear in the input
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with each abscissa value.
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The next argument is
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.IR n .
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.TP
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.B -s
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Save screen; no new page for this graph.
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.TP
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.B -x l
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If
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.B l
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is present,
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.IR x -axis
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is logarithmic.
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Next 1 (or 2) arguments are lower (and upper)
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.I x
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limits.
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Third argument, if present, is grid spacing on
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.I x
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axis.
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Normally these quantities are determined automatically.
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.TP
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.B -y l
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Similarly for
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.IR y .
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.TP
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.B -e
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Make automatically determined
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.I x
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and
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.I y
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scales equal.
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.TP
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.B -h
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Next argument is fraction of space for height.
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.TP
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.B -w
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Similarly for width.
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.TP
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.B -r
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Next argument is fraction of space to move right before plotting.
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.TP
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.B -u
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Similarly to move up before plotting.
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.TP
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.B -t
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Transpose horizontal and vertical axes.
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(Option
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.B -a
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now applies to the vertical axis.)
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.PP
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If a specified lower limit exceeds the upper limit,
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the axis
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is reversed.
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.SH SOURCE
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.B /sys/src/cmd/graph
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.SH "SEE ALSO"
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.IR plot (1),
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.IR grap (1)
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.SH BUGS
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Segments that run out of bounds are dropped, not windowed.
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Logarithmic axes may not be reversed.
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Option
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.B -e
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actually makes automatic limits, rather than automatic scaling,
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equal.
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61
man/man1/plot.1
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61
man/man1/plot.1
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.TH PLOT 1
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.SH NAME
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plot \- graphics filter
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.SH SYNOPSIS
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.B plot
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[
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.I file ...
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]
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.SH DESCRIPTION
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.I Plot
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interprets plotting instructions (see
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.IR plot (6))
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from the
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.I files
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or standard input,
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drawing the results in a newly created
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.IR rio (1)
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window.
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Plot persists until a newline is typed in the window.
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Various options may be interspersed with the
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.I file
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arguments; they take effect at the given point in processing.
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Options are:
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.TP "\w'\fL-g \fIgrade\fLXX'u"
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.B -d
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Double buffer: accumulate the plot off-screen and write to the screen all at once
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when an erase command is encountered or at end of file.
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.TP
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.B -e
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Erase the screen.
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.TP
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.BI -c " col"
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Set the foreground color (see
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.IR plot (6)
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for color names).
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.TP
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.BI -f " fill"
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Set the background color.
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.TP
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.BI -g " grade"
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Set the quality factor for arcs.
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Higher grades give better quality.
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.TP
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.BI -p " col"
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Set the pen color.
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.TP
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.BI -w
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Pause until a newline is typed on standard input.
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.TP
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.B -C
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Close the current plot.
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.TP
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.B -W " x0,y0,x1,y1"
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Specify the bounding rectangle of plot's window.
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By default it uses a 512×512 window in the
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middle of the screen.
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.SH SOURCE
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.B /sys/src/cmd/plot
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.SH "SEE ALSO"
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.IR rio (1),
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.IR plot (6)
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87
man/man5/venti.conf.5
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87
man/man5/venti.conf.5
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.TH VENTI.CONF 6
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.SH NAME
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venti.conf \- a venti configuration file
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.SH DESCRIPTION
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A venti configuration file enumerates the various index sections and
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arenas that constitute a venti system.
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The components are indicated by the name of the file, typically
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a disk partition, in which they reside. The configuration
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file is the only location that file names are used. Internally,
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venti uses the names assigned when the components were formatted
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with
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.I fmtarenas
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or
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.I fmtisect
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(see
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.IR ventiaux (8)).
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In particular, by changing the configuration a
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component can be copied to a different file.
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.PP
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The configuration file consists of lines in the form described below.
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Lines starting with
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.B #
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are comments.
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.TP
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.BI index " name
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Names the index for the system.
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.TP
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.BI arenas " file
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.I File
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contains a collection of arenas, formatted using
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.IR fmtarenas .
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.TP
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.BI isect " file
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.I File
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contains an index section, formatted using
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.IR fmtisect .
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.PP
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After formatting a venti system using
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.IR fmtindex ,
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the order of arenas and index sections should not be changed.
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Additional arenas can be appended to the configuration.
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.PP
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The configuration file optionally holds configuration parameters
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for the venti server itself.
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These are:
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.TP
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.BI mem " cachesize
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.TP
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.BI bcmem " blockcachesize
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.TP
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.BI icmem " indexcachesize
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.TP
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.BI addr " ventiaddress
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.TP
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.BI httpaddr " httpaddress
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.TP
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.B queuewrites
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.PD
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See
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.IR venti (8)
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for descriptions of these variables.
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.SH EXAMPLE
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.EX
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# a sample venti configuration file
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#
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# formatted with
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# venti/fmtarenas arena. /tmp/disks/arenas
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# venti/fmtisect isect0 /tmp/disks/isect0
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# venti/fmtisect isect1 /tmp/disks/isect1
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# venti/fmtindex venti.conf
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#
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# server is started with
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# venti/venti
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# the name of the index
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index main
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# the index sections
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isect /tmp/disks/isect0
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isect /tmp/disks/isect1
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# the arenas
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arenas /tmp/disks/arenas
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.EE
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.SH "SEE ALSO"
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.IR venti (8),
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.IR ventiaux (8)
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232
man/man8/venti.8
Normal file
232
man/man8/venti.8
Normal file
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@ -0,0 +1,232 @@
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.TH VENTI 8
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.SH NAME
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venti \- an archival block storage server
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.SH SYNOPSIS
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.B venti/venti
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[
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.B -dsw
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]
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[
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.B -a
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.I ventiaddress
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]
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[
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.B -B
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.I blockcachesize
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]
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[
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.B -c
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.I config
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]
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[
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.B -C
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.I cachesize
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]
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[
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.B -h
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.I httpaddress
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]
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[
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.B -I
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.I icachesize
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]
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.PP
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.B venti/sync
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[
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.B -h
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.I host
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]
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.SH DESCRIPTION
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.I Venti
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is a block storage server intended for archival data.
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In a Venti server,
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the SHA1 hash of a block's contents acts as the block
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identifier for read and write operations.
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This approach enforces a write-once policy, preventing accidental or
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malicious destruction of data. In addition, duplicate copies of a
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block are coalesced, reducing the consumption of storage and
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simplifying the implementation of clients.
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.PP
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Storage for
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.I venti
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consists of a data log and an index, both of which
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can be spread across multiple files.
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The files containing the data log are themselves divided into self-contained sections called arenas.
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Each arena contains a large number of data blocks and is sized to
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facilitate operations such as copying to removable media.
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The index provides a mapping between the a Sha1 fingerprint and
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the location of the corresponding block in the data log.
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.PP
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The index and data log are typically stored on raw disk partitions.
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To improve the robustness, the data log should be stored on
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a device that provides RAID functionality. The index does
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not require such protection, since if necessary, it can
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can be regenerated from the data log.
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The performance of
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.I venti
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is typically limited to the random access performance
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of the index. This performance can be improved by spreading the
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index accross multiple disks.
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.PP
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The storage for
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.I venti
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is initialized using
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.IR fmtarenas ,
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.IR fmtisect ,
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and
|
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.I fmtindex
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(see
|
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.IR ventiaux (8)).
|
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A configuration file,
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.IR venti.conf (6),
|
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ties the index sections and data arenas together.
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.PP
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A Venti
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server is accessed via an undocumented network protocol.
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Two client applications are included in this distribution:
|
||||
.IR vac (1)
|
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and
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.IR vacfs (4).
|
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.I Vac
|
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copies files from a Plan 9 file system to Venti, creating an
|
||||
archive and returning the fingerprint of the root.
|
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This archive can be mounted in Plan 9 using
|
||||
.IR vacfs .
|
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These two commands enable a rudimentary backup system.
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A future release will include a Plan 9 file system that uses
|
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Venti as a replacement for the WORM device of
|
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.IR fs (4).
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.PP
|
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The
|
||||
.I venti
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server provides rudimentary status information via
|
||||
a built-in http server. The URL files it serves are:
|
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.TP
|
||||
.B stats
|
||||
Various internal statistics.
|
||||
.TP
|
||||
.B index
|
||||
An enumeration of the index sections and all non empty arenas, including various statistics.
|
||||
.TP
|
||||
.B storage
|
||||
A summary of the state of the data log.
|
||||
.TP
|
||||
.B xindex
|
||||
An enumeration of the index sections and all non empty arenas, in XML format.
|
||||
.PP
|
||||
Several auxiliary utilities (see
|
||||
.IR ventiaux (8))
|
||||
aid in maintaining the storage for Venti.
|
||||
With the exception of
|
||||
.I rdarena ,
|
||||
these utilities should generally be run after killing the
|
||||
.I venti
|
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server.
|
||||
The utilities are:
|
||||
.TP
|
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.I checkarenas
|
||||
Check the integrity, and optionally fix, Venti arenas.
|
||||
.TP
|
||||
.I checkindex
|
||||
Check the integrity, and optionally fix, a Venti index.
|
||||
.TP
|
||||
.I buildindex
|
||||
Rebuild a Venti index from scratch.
|
||||
.TP
|
||||
.I rdarena
|
||||
Extract a Venti arena and write to standard output.
|
||||
.PD
|
||||
.PP
|
||||
Options to
|
||||
.I venti
|
||||
are:
|
||||
.TP
|
||||
.BI -a " ventiaddress
|
||||
The network address on which the server listens for incoming connections.
|
||||
The default is
|
||||
.LR tcp!*!venti .
|
||||
.TP
|
||||
.BI -B " blockcachesize
|
||||
The size, in bytes, of memory allocated to caching raw disk blocks.
|
||||
.TP
|
||||
.BI -c " config
|
||||
Specifies the
|
||||
Venti
|
||||
configuration file.
|
||||
Defaults to
|
||||
.LR venti.conf .
|
||||
.TP
|
||||
.BI -C " cachesize
|
||||
The size, in bytes, of memory allocated to caching
|
||||
Venti
|
||||
blocks.
|
||||
.TP
|
||||
.BI -d
|
||||
Produce various debugging information on standard error.
|
||||
.TP
|
||||
.BI -h " httpaddress
|
||||
The network address of Venti's built-in
|
||||
http
|
||||
server.
|
||||
The default is
|
||||
.LR tcp!*!http .
|
||||
.TP
|
||||
.BI -I " icachesize
|
||||
The size, in bytes, of memory allocated to caching the index mapping fingerprints
|
||||
to locations in
|
||||
.IR venti 's
|
||||
data log.
|
||||
.TP
|
||||
.B -s
|
||||
Do not run in the background.
|
||||
Normally,
|
||||
the foreground process will exit once the Venti server
|
||||
is initialized and ready for connections.
|
||||
.TP
|
||||
.B -w
|
||||
Enable write buffering. This option increase the performance of writes to
|
||||
.I venti
|
||||
at the cost of returning success to the client application before the
|
||||
data has been written to disk.
|
||||
The server implements a
|
||||
.I sync
|
||||
rpc that waits for completion of all the writes buffered at the time
|
||||
the rpc was received.
|
||||
Applications such as
|
||||
.IR vac (1)
|
||||
and the
|
||||
.I sync
|
||||
command described below
|
||||
use this rpc to make sure that the data is correctly written to disk.
|
||||
Use of this option is recommended.
|
||||
.PD
|
||||
.PP
|
||||
The units for the various cache sizes above can be specified by appending a
|
||||
.LR k ,
|
||||
.LR m ,
|
||||
or
|
||||
.LR g
|
||||
to indicate kilobytes, megabytes, or gigabytes respectively.
|
||||
The command line options override options found in the
|
||||
.IR venti.conf (6)
|
||||
file.
|
||||
.PP
|
||||
.I Sync
|
||||
connects to a running Venti server and executes a sync rpc
|
||||
(described with the
|
||||
.B -w
|
||||
option above).
|
||||
If sync exits successfully, it means that all writes buffered at the
|
||||
time the command was issued are now on disk.
|
||||
.SH SOURCE
|
||||
.B /sys/src/cmd/venti
|
||||
.SH "SEE ALSO"
|
||||
.IR venti.conf (6),
|
||||
.IR ventiaux (8),
|
||||
.IR vac (1),
|
||||
.IR vacfs (4).
|
||||
.br
|
||||
Sean Quinlan and Sean Dorward,
|
||||
``Venti: a new approach to archival storage'',
|
||||
.I "Usenix Conference on File and Storage Technologies" ,
|
||||
2002.
|
||||
504
man/man8/ventiaux.8
Normal file
504
man/man8/ventiaux.8
Normal file
|
|
@ -0,0 +1,504 @@
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.TH VENTIAUX 8
|
||||
.SH NAME
|
||||
buildindex,
|
||||
checkarenas,
|
||||
checkindex,
|
||||
conf,
|
||||
copy,
|
||||
fmtarenas,
|
||||
fmtindex,
|
||||
fmtisect,
|
||||
rdarena,
|
||||
rdarenablocks,
|
||||
read,
|
||||
wrarenablocks,
|
||||
write \- Venti maintenance and debugging commands
|
||||
.SH SYNOPSIS
|
||||
.B venti/buildindex
|
||||
[
|
||||
.B -B
|
||||
.I blockcachesize
|
||||
]
|
||||
[
|
||||
.B -Z
|
||||
]
|
||||
.I venti.config
|
||||
.I tmp
|
||||
.PP
|
||||
.B venti/checkarenas
|
||||
[
|
||||
.B -afv
|
||||
]
|
||||
.I file
|
||||
.PP
|
||||
.B venti/checkindex
|
||||
[
|
||||
.B -f
|
||||
]
|
||||
[
|
||||
.B -B
|
||||
.I blockcachesize
|
||||
]
|
||||
.I venti.config
|
||||
.I tmp
|
||||
.PP
|
||||
.B venti/conf
|
||||
[
|
||||
.B -w
|
||||
]
|
||||
.I partition
|
||||
[
|
||||
.I configfile
|
||||
]
|
||||
.PP
|
||||
.B venti/copy
|
||||
[
|
||||
.B -f
|
||||
]
|
||||
.I src
|
||||
.I dst
|
||||
.I score
|
||||
[
|
||||
.I type
|
||||
]
|
||||
.PP
|
||||
.B venti/fmtarenas
|
||||
[
|
||||
.B -Z
|
||||
]
|
||||
[
|
||||
.B -a
|
||||
.I arenasize
|
||||
]
|
||||
[
|
||||
.B -b
|
||||
.I blocksize
|
||||
]
|
||||
.I name
|
||||
.I file
|
||||
.PP
|
||||
.B venti/fmtindex
|
||||
[
|
||||
.B -a
|
||||
]
|
||||
.I venti.config
|
||||
.PP
|
||||
.B venti/fmtisect
|
||||
[
|
||||
.B -Z
|
||||
]
|
||||
[
|
||||
.B -b
|
||||
.I blocksize
|
||||
]
|
||||
.I name
|
||||
.I file
|
||||
.PP
|
||||
.B venti/rdarena
|
||||
[
|
||||
.B -v
|
||||
]
|
||||
.I arenapart
|
||||
.I arenaname
|
||||
.PP
|
||||
.B venti/read
|
||||
[
|
||||
.B -h
|
||||
.I host
|
||||
]
|
||||
.I score
|
||||
[
|
||||
.I type
|
||||
]
|
||||
.PP
|
||||
.B venti/wrarena
|
||||
[
|
||||
.B -o
|
||||
.I fileoffset
|
||||
]
|
||||
[
|
||||
.B -h
|
||||
.I host
|
||||
]
|
||||
.I arenafile
|
||||
[
|
||||
.I clumpoffset
|
||||
]
|
||||
.PP
|
||||
.B venti/write
|
||||
[
|
||||
.B -h
|
||||
.I host
|
||||
]
|
||||
[
|
||||
.B -t
|
||||
.I type
|
||||
]
|
||||
[
|
||||
.B -z
|
||||
]
|
||||
.SH DESCRIPTION
|
||||
These commands aid in the setup, maintenance, and debugging of
|
||||
Venti servers.
|
||||
See
|
||||
.IR venti (8)
|
||||
and
|
||||
.IR venti.conf (6)
|
||||
for an overview of the data structures stored by Venti.
|
||||
.PP
|
||||
Note that the units for the various sizes in the following
|
||||
commands can be specified by appending
|
||||
.LR k ,
|
||||
.LR m ,
|
||||
or
|
||||
.LR g
|
||||
to indicate kilobytes, megabytes, or gigabytes respectively.
|
||||
.PP
|
||||
.I Buildindex
|
||||
populates the index for the Venti system described in
|
||||
.IR venti.config .
|
||||
The index must have previously been formatted using
|
||||
.IR fmtindex .
|
||||
This command is typically used to build a new index for a Venti
|
||||
system when the old index becomes too small, or to rebuild
|
||||
an index after media failure.
|
||||
Small errors in an index can usually be fixed with
|
||||
.IR checkindex .
|
||||
.PP
|
||||
The
|
||||
.I tmp
|
||||
file, usually a disk partition, must be large enough to store a copy of the index.
|
||||
This temporary space is used to perform a merge sort of index entries
|
||||
generated by reading the arenas.
|
||||
.PP
|
||||
Options to
|
||||
.I buildindex
|
||||
are:
|
||||
.TP
|
||||
.BI -B " blockcachesize
|
||||
The amount of memory, in bytes, to use for caching raw disk accesses while running
|
||||
.IR buildindex .
|
||||
(This is not a property of the created index.)
|
||||
The default is 8k.
|
||||
.TP
|
||||
.B -Z
|
||||
Do not zero the index.
|
||||
This option should only be used when it is known that the index was already zeroed.
|
||||
.PD
|
||||
.PP
|
||||
.I Checkarenas
|
||||
examines the Venti arenas contained in the given
|
||||
.IR file .
|
||||
The program detects various error conditions, and optionally attempts
|
||||
to fix any errors that are found.
|
||||
.PP
|
||||
Options to
|
||||
.I checkarenas
|
||||
are:
|
||||
.TP
|
||||
.B -a
|
||||
For each arena, scan the entire data section.
|
||||
If this option is omitted, only the end section of
|
||||
the arena is examined.
|
||||
.TP
|
||||
.B -f
|
||||
Attempt to fix any errors that are found.
|
||||
.TP
|
||||
.B -v
|
||||
Increase the verbosity of output.
|
||||
.PD
|
||||
.PP
|
||||
.I Checkindex
|
||||
examines the Venti index described in
|
||||
.IR venti.config .
|
||||
The program detects various error conditions including:
|
||||
blocks that are not indexed, index entries for blocks that do not exist,
|
||||
and duplicate index entries.
|
||||
If requested, an attempt can be made to fix errors that are found.
|
||||
.PP
|
||||
The
|
||||
.I tmp
|
||||
file, usually a disk partition, must be large enough to store a copy of the index.
|
||||
This temporary space is used to perform a merge sort of index entries
|
||||
generated by reading the arenas.
|
||||
.PP
|
||||
Options to
|
||||
.I checkindex
|
||||
are:
|
||||
.TP
|
||||
.BI -B " blockcachesize
|
||||
The amount of memory, in bytes, to use for caching raw disk accesses while running
|
||||
.IR checkindex .
|
||||
The default is 8k.
|
||||
.TP
|
||||
.B -f
|
||||
Attempt to fix any errors that are found.
|
||||
.PD
|
||||
.PP
|
||||
.I Fmtarenas
|
||||
formats the given
|
||||
.IR file ,
|
||||
typically a disk partition, into a number of
|
||||
Venti
|
||||
arenas.
|
||||
The arenas are given names of the form
|
||||
.IR name%d ,
|
||||
where
|
||||
.I %d
|
||||
is replaced with a sequential number starting at 0.
|
||||
.PP
|
||||
Options to
|
||||
.I fmtarenas
|
||||
are:
|
||||
.TP
|
||||
.BI -a " arenasize
|
||||
The arenas are of
|
||||
.I arenasize
|
||||
bytes. The default is 512 megabytes, which was selected to provide a balance
|
||||
between the number of arenas and the ability to copy an arena to external
|
||||
media such as recordable CDs and tapes.
|
||||
.TP
|
||||
.BI -b " blocksize
|
||||
The size, in bytes, for read and write operations to the file.
|
||||
The size is recorded in the file, and is used by applications that access the arenas.
|
||||
The default is 8k.
|
||||
.TP
|
||||
.B -Z
|
||||
Do not zero the data sections of the arenas.
|
||||
Using this option reduces the formatting time
|
||||
but should only be used when it is known that the file was already zeroed.
|
||||
.PD
|
||||
.I Fmtindex
|
||||
takes the
|
||||
.IR venti.conf (6)
|
||||
file
|
||||
.I venti.config
|
||||
and initializes the index sections to form a usable index structure.
|
||||
The arena files and index sections must have previously been formatted
|
||||
using
|
||||
.I fmtarenas
|
||||
and
|
||||
.I fmtisect
|
||||
respectively.
|
||||
.PP
|
||||
The function of a Venti index is to map a SHA1 fingerprint to a location
|
||||
in the data section of one of the arenas. The index is composed of
|
||||
blocks, each of which contains the mapping for a fixed range of possible
|
||||
fingerprint values.
|
||||
.I Fmtindex
|
||||
determines the mapping between SHA1 values and the blocks
|
||||
of the collection of index sections. Once this mapping has been determined,
|
||||
it cannot be changed without rebuilding the index.
|
||||
The basic assumption in the current implementation is that the index
|
||||
structure is sufficiently empty that individual blocks of the index will rarely
|
||||
overflow. The total size of the index should be about 2% to 10% of
|
||||
the total size of the arenas, but the exact depends both the index block size
|
||||
and the compressed size of block stored to Venti.
|
||||
.PP
|
||||
.I Fmtindex
|
||||
also computes a mapping between a linear address space and
|
||||
the data section of the collection of arenas. The
|
||||
.B -a
|
||||
option can be used to add additional arenas to an index.
|
||||
To use this feature,
|
||||
add the new arenas to
|
||||
.I venti.config
|
||||
after the existing arenas and then run
|
||||
.I fmtindex
|
||||
.BR -a .
|
||||
.PP
|
||||
A copy of the above mappings is stored in the header for each of the index sections.
|
||||
These copies enable
|
||||
.I buildindex
|
||||
to restore a single index section without rebuilding the entire index.
|
||||
.PP
|
||||
.I Fmtisect
|
||||
formats the given
|
||||
.IR file ,
|
||||
typically a disk partition, as a Venti index section with the specified
|
||||
.IR name .
|
||||
One or more formatted index sections are combined into a Venti
|
||||
index using
|
||||
.IR fmtindex .
|
||||
Each of the index sections within an index must have a unique name.
|
||||
.PP
|
||||
Options to
|
||||
.I fmtisect
|
||||
are:
|
||||
.TP
|
||||
.BI -b " blocksize
|
||||
The size, in bytes, for read and write operations to the file.
|
||||
All the index sections within a index must have the same block size.
|
||||
The default is 8k.
|
||||
.TP
|
||||
.B -Z
|
||||
Do not zero the index.
|
||||
Using this option reduces the formatting time
|
||||
but should only be used when it is known that the file was already zeroed.
|
||||
.PD
|
||||
.PP
|
||||
.I Rdarena
|
||||
extracts the named
|
||||
.I arena
|
||||
from the arena partition
|
||||
.I arenapart
|
||||
and writes this arena to standard output.
|
||||
This command is typically used to back up an arena to external media.
|
||||
The
|
||||
.B -v
|
||||
option generates more verbose output on standard error.
|
||||
.PP
|
||||
.I Wrarena
|
||||
writes the blocks contained in the arena
|
||||
.I arenafile
|
||||
(typically, the output of
|
||||
.IR rdarena )
|
||||
to a Venti server.
|
||||
It is typically used to reinitialize a Venti server from backups of the arenas.
|
||||
For example,
|
||||
.IP
|
||||
.EX
|
||||
venti/rdarena /dev/sdC0/arenas arena.0 >external.media
|
||||
venti/wrarena -h venti2 external.media
|
||||
.EE
|
||||
.LP
|
||||
writes the blocks contained in
|
||||
.B arena.0
|
||||
to the Venti server
|
||||
.B venti2
|
||||
(typically not the one using
|
||||
.BR /dev/sdC0/arenas ).
|
||||
.PP
|
||||
The
|
||||
.B -o
|
||||
option specifies that the arena starts at byte
|
||||
.I fileoffset
|
||||
(default
|
||||
.BR 0 )
|
||||
in
|
||||
.I arenafile .
|
||||
This is useful for reading directly from
|
||||
the Venti arena partition:
|
||||
.IP
|
||||
.EX
|
||||
venti/wrarena -h venti2 -o 335872 /dev/sdC0/arenas
|
||||
.EE
|
||||
.LP
|
||||
(In this example, 335872 is the offset shown in the Venti
|
||||
server's index list (344064) minus one block (8192).
|
||||
You will need to substitute your own arena offsets
|
||||
and block size.)
|
||||
.PP
|
||||
Finally, the optional
|
||||
.I offset
|
||||
argument specifies that the writing should begin with the
|
||||
clump starting at
|
||||
.I offset
|
||||
within the arena.
|
||||
.I Wrarena
|
||||
prints the offset it stopped at (because there were no more data blocks).
|
||||
This could be used to incrementally back up a Venti server
|
||||
to another Venti server:
|
||||
.IP
|
||||
.EX
|
||||
last=`{cat last}
|
||||
venti/wrarena -h venti2 -o 335872 /dev/sdC0/arenas $last >output
|
||||
awk '/^end offset/ { print $3 }' offset >last
|
||||
.EE
|
||||
.LP
|
||||
Of course, one would need to add wrapper code to keep track
|
||||
of which arenas have been processed.
|
||||
See
|
||||
.B /sys/src/cmd/venti/backup.example
|
||||
for a version that does this.
|
||||
.PP
|
||||
.I Read
|
||||
and
|
||||
.I write
|
||||
read and write blocks from a running Venti server.
|
||||
They are intended to ease debugging of the server.
|
||||
The default
|
||||
.I host
|
||||
is the environment variable
|
||||
.BR $venti ,
|
||||
followed by the network metaname
|
||||
.BR $venti .
|
||||
The
|
||||
.I type
|
||||
is the decimal type of block to be read or written.
|
||||
If no
|
||||
.I type
|
||||
is specified for
|
||||
.I read ,
|
||||
all types are tried, and a command-line is printed to
|
||||
show the type that eventually worked.
|
||||
If no
|
||||
.I type
|
||||
is specified for
|
||||
.I write ,
|
||||
.B VtDataType
|
||||
(13)
|
||||
is used.
|
||||
.I Read
|
||||
reads the block named by
|
||||
.I score
|
||||
(a SHA1 hash)
|
||||
from the Venti server and writes it to standard output.
|
||||
.I Write
|
||||
reads a block from standard input and attempts to write
|
||||
it to the Venti server.
|
||||
If successful, it prints the score of the block on the server.
|
||||
.PP
|
||||
.I Copy
|
||||
walks the entire tree of blocks rooted at
|
||||
.I score ,
|
||||
copying all the blocks visited during the walk from
|
||||
the Venti server at network address
|
||||
.I src
|
||||
to the Venti server at network address
|
||||
.I dst .
|
||||
If
|
||||
.I type
|
||||
(a decimal block type for
|
||||
.IR score )
|
||||
is omitted, all types will be tried in sequence
|
||||
until one is found that works.
|
||||
The
|
||||
.B -f
|
||||
flag runs the copy in ``fast'' mode: if a block is already on
|
||||
.IR dst ,
|
||||
the walk does not descend below it, on the assumption that all its
|
||||
children are also already on
|
||||
.IR dst .
|
||||
Without this flag, the copy often transfers many times more
|
||||
data than necessary.
|
||||
.PP
|
||||
To make it easier to bootstrap servers, the configuration
|
||||
file can be stored at the beginning of any Venti partitions using
|
||||
.IR conf .
|
||||
A partition so branded with a configuration file can
|
||||
be used in place of a configuration file when invoking any
|
||||
of the venti commands.
|
||||
By default,
|
||||
.I conf
|
||||
prints the configuration stored in
|
||||
.IR partition .
|
||||
When invoked with the
|
||||
.B -w
|
||||
flag,
|
||||
.I conf
|
||||
reads a configuration file from
|
||||
.I configfile
|
||||
(or else standard input)
|
||||
and stores it in
|
||||
.IR partition .
|
||||
.SH SOURCE
|
||||
.B /sys/src/cmd/venti
|
||||
.SH "SEE ALSO"
|
||||
.IR venti (8),
|
||||
.IR venti.conf (6)
|
||||
.SH BUGS
|
||||
.I Buildindex
|
||||
should allow an individual index section to be rebuilt.
|
||||
The merge sort could be performed in the space used to store the
|
||||
index rather than requiring a temporary file.
|
||||
Loading…
Add table
Add a link
Reference in a new issue