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2 {
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6 \usepackage{lmodern}
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8 \setbeamercovered{transparent=25}
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10 \mode<article>
11 {
12 \usepackage{url}
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22 \usepackage{alltt}
23 \usepackage{listings}
24 \usepackage{svgcolor}
25 \usepackage[english]{babel}
26 \usepackage[latin1]{inputenc}
27 % or whatever
29 \usepackage[T1]{fontenc}
30 % Or whatever. Note that the encoding and the font should match. If T1
31 % does not look nice, try deleting the line with the fontenc.
33 \title
34 {RRDtool by Example}
36 \author
37 {Tobias Oetiker}
39 \institute
40 {OETIKER+PARTNER AG}
42 \date[LISA 2008] % (optional, should be abbreviation of conference name)
43 {21. Large Installation System Administration Conference}
45 \mode<presentation>{\subject{RRDtool tutorial based on example use}}
47 \mode<presentation>{
48 \lstset{%
49 language=Perl,%
50 numbers=left,%
51 basicstyle=\ttfamily\footnotesize\color{black},%
52 keywordstyle=\color{darkgreen},%
53 % identifyerstyle=\color{brown},%
54 commentstyle=\color{mediumpurple},%
55 stringstyle=\color{dimgray},
56 numberstyle=\ttfamily\scriptsize\color{darkgray},
57 showstringspaces=false
58 }
59 }
60 \mode<article>{
61 \lstset{%
62 language=Perl,%
63 numbers=left,%
64 basicstyle=\ttfamily\footnotesize,%
65 keywordstyle=\bfseries,%
66 numberstyle=\ttfamily\scriptsize,
67 % identifyerstyle=\color{brown},%
68 commentstyle=\itshape,%
69 stringstyle=\color{black},
70 showstringspaces=false
71 }
72 }
74 \begin{document}
76 \mode<article>{\maketitle}
78 \begin{frame}<presentation>
79 \titlepage
80 \end{frame}
82 \mode<articel>{\tableofcontents}
84 \section{A different kind of Database}
86 \begin{frame}{creating a simple rrd}
87 \lstinputlisting[language=bash,firstline=0,lastline=11]{ex/create-first.sh}
88 One Datasource, 4 Round Robin Archives
89 \end{frame}
91 \begin{frame}{feeding data}
92 \lstinputlisting[language=bash,firstline=13,lastline=21]{ex/create-first.sh}
93 Feed in some data. One or several updates at once.
94 \end{frame}
96 \begin{frame}[allowframebreaks]{inside the database}
97 \lstinputlisting[language=xml,basicstyle=\ttfamily\scriptsize]{ex/create-first.xml}
98 \end{frame}
100 \mode<article>{
101 The xml dump of the rrd file shows an approximation of the on-disk
102 structure of the database. The rra database sections are re-ordered, so that
103 they are in chronological order with the oldest at the top. Also the
104 cdp sections are stored right after the header. The idea behind this
105 design is that data that get written on every update is as close
106 together as possible.}
108 \begin{frame}{rrd features}
109 \begin{itemize}
110 \item optimized for time-series data
111 \item fixed size rotating data store
112 \item constant on-disk size
113 \item no maintenance
114 \item on the fly consolidation
115 \end{itemize}
116 \end{frame}
118 \begin{frame}[fragile]{on-disk structure}
119 \begin{alltt}
120 +-------------------------------+
121 | Static Header | \textrm{RRD cookie, DB cfg}
122 |-------------------------------|\pause
123 : Data Source (DS) Definitions :
124 |-------------------------------|\pause
125 : RR Archive (RRA) Definitions :
126 |===============================|\pause
127 | Live Head | \textrm{last update time}
128 |-------------------------------|\pause
129 : PDP Prep per DS : \textrm{last value for diff}
130 |-------------------------------|\pause
131 : CDP Prep per RRA and DS : \textrm{intermediate storage}
132 |-------------------------------|\pause
133 : RRA Pointers :
134 |===============================|\pause
135 : Round Robin Archives (RRA) :
136 +-------------------------------+
137 \end{alltt}
138 \end{frame}
140 \begin{frame}{irregular data arrival intervals}
141 \lstinputlisting[language=bash,lastline=19]{ex/update-real.sh}
142 \end{frame}
144 \mode<article>{To try things out lets assume that data arrives at
145 irregular intervals. This is counter data. By synchronizing the
146 data values with the arrival time we should get a constant rate
147 stored in the database.}
149 \begin{frame}{database after the irregular updates}
150 \lstinputlisting[language=bash,firstline=20]{ex/update-real.sh}
151 \lstinputlisting[language=bash]{ex/update-real.txt}
153 \begin{itemize}
154 \item rrdtool re-binning at work
155 \item major difference to a normal db
156 \item all bins contain 1.0
157 \item the time is the 'end-time' of the bin.
158 \end{itemize}
159 \end{frame}
161 \mode<article>{\newpage}
162 \begin{frame}{optimizing your rrds}
163 \begin{itemize}
164 \item update of multi DS RRD is cheep
165 \item single update interval per RRD
166 \item RRD modification is expensive
167 \item RRD size and update performance are independent
168 \item RRA complexity affects update performance
169 \end{itemize}
170 \end{frame}
172 \mode<article>{As long as your system is small (a few hundred RRDs)
173 you should optimize for convenience. Only keep DSes together
174 in one RRD that are tightly bound. For everything else
175 create separate RRDs.}
177 \mode<article>{\newpage}
179 \begin{frame}{fetching data}
180 fetch is for reading data from an rrd
181 \lstinputlisting[language=bash,firstline=8,lastline=9]{ex/catch-fetch.sh}
182 \begin{itemize}
183 \item one RRA with two 300s entries
184 \item one RRA with three 600s entries
185 \end{itemize}
186 \end{frame}
188 \begin{frame}[fragile]{playing catch with fetch}
189 first pull 300 seconds
190 \begin{verbatim}
191 > rrdtool fetch x.rrd -r 300 \
192 -s 1200000600 -e 1200000900 AVERAGE
194 1200000900: 4.0000000000e+01
195 1200001200: 5.0000000000e+01
196 \end{verbatim}
198 then pull 900 seconds
199 \begin{verbatim}
200 > rrdtool fetch x.rrd -r300 \
201 -s 1200000000 -e 1200000900 AVERAGE
203 1200000600: 2.5000000000e+01
204 1200001200: 4.5000000000e+01
205 \end{verbatim}
206 \end{frame}
208 \begin{frame}{fetch recap}
209 \begin{itemize}
210 \item looking for complete coverage
211 \item resolution is only a suggestion
212 \item time stamp in output marks the END of the period
213 \item end-time differences caused problems
214 \item since 1.3, only the start-time is relevant for coverage
215 \item outside the rra everything is NaN
216 \end{itemize}
217 \end{frame}
219 \begin{frame}{the size of an rrd - code}
220 \lstinputlisting{ex/rrd-size.pl}
221 \end{frame}
223 \mode<article>{\newpage}
225 \begin{frame}{the size of an rrd - result}
226 \lstinputlisting{ex/rrd-size.txt}
227 \begin{itemize}
228 \item overhead is minimal
229 \item 8 byte per double
230 \item \ldots per datasource
231 \item \ldots per RRA
232 \item \ldots per RRA row
233 \end{itemize}
234 \end{frame}
236 \mode<article>{The rrd format is highly efficient at storing non
237 sparse data. The overhead for an extra RRA or DS is normally a few
238 bytes on top of the 8 byte per double.}
240 \mode<article>{\newpage}
242 \section{Graphing}
243 \begin{frame}[fragile]{rrdgraph syntax 101}
244 for graph command syntax, there are two basic rules:\pause
245 \begin{enumerate}
246 \item \texttt{-{}-options} start with a double dash\pause
247 \item graphing instructions start with a letter
248 \end{enumerate}
250 \pause
251 \begin{center}
252 \renewcommand{\tabcolsep}{0.4cm}
253 \renewcommand{\arraystretch}{2}
255 \begin{tabular}{|l|}\hline
256 \begin{minipage}[t]{0.7\textwidth}
257 \begin{alltt}
258 rrdtool graph \textit{output}
259 DEF:var=\textit{rrd}:\textit{DS}:\textit{AVARAGE}
260 LINE:var#\textit{hex-rgb-color}:Comment
262 \end{alltt}
263 \end{minipage}\\\hline
264 \end{tabular}
265 \end{center}
267 \texttt{DEF} and \texttt{LINE} are \emph{graphing instructions}.
268 \end{frame}
270 \mode<article>{The rrd graph command is the most versatile of all rrdtool
271 commands. It comes with its own little language, optimized for
272 drawing graphs. There are two kinds of arguments. The options
273 which start with a double-dash and the graphing instructions that
274 start with an uppercase letter.}
276 \begin{frame}{normal line}
277 \addgraph{LINE}
278 \end{frame}
280 \begin{frame}{lower limit}
281 \addgraph{LINE-lower}
282 \end{frame}
284 \mode<article>{Unless you are a banker and are you drawing stock diagrams,
285 make sure your graph displays the zero-y-value. Otherwise it is
286 pretty difficult to judge the meaning of the graph since perspective
287 is limited to the numbers on the y-axis.}
289 \begin{frame}{slope mode}
290 \addgraph{LINE-slope}
291 \end{frame}
293 \mode<article>{RRD graphs are pretty blocky. This is on purpose, since
294 the data is blocky too. The slope mode is a little concession. It
295 tilts the vertical connections between the 'blocks' by one pixel.}
297 \begin{frame}{anti-anti-aliasing: graph}
298 \addgraph{LINE-graph-mono}
299 \end{frame}
301 \begin{frame}{anti-anti-aliasing: font}
302 \addgraph{LINE-font-mono}
303 \end{frame}
305 \mode<article>{\newpage}
306 \begin{frame}{line width}
307 \addgraph{LINE-width}
308 \end{frame}
310 \begin{frame}{dashed line}
311 \addgraph{LINE-dash}
312 \end{frame}
314 \mode<article>{The numbers are an ON-OFF-ON-OFF-\ldots pattern. The
315 \texttt{dash-offset} property lets you shift the dashing of the line
316 to the right.}
318 \begin{frame}{DEF with :step}
319 \addgraph{DEF-step}
320 \end{frame}
323 \begin{frame}{DEF with :start}
324 \addgraph{DEF-start}
325 \end{frame}
326 \mode<article>{\newpage}
328 \begin{frame}{DEF with :reduce}
329 \addgraph{DEF-reduce}
330 \end{frame}
332 \begin{frame}{AREA simple}
333 \addgraph{AREA-simple}
334 \end{frame}
336 \mode<article>{\newpage}
337 \begin{frame}{two AREAs}
338 \addgraph{AREA-two}
339 \end{frame}
341 \begin{frame}{transparent AREA}
342 \addgraph{AREA-trans}
343 \end{frame}
345 \mode<article>{RRDtool creates real alpha transparency. You can set
346 the whole graph to be transparent by setting the
347 graph CANVAS and BACKGROUND colors to transparent.}
349 \mode<article>{\newpage}
350 \begin{frame}{stacked AREA}
351 \addgraph{AREA-stack}
352 \end{frame}
354 \mode<article>{\newpage}
356 \begin{frame}{time shift}
357 \addgraph{SHIFT-simple}
358 \end{frame}
360 \begin{frame}{shifting with extra data}
361 \addgraph{SHIFT-startdef}
362 \end{frame}
364 \mode<article>{A normal \texttt{DEF} line requests exactly as much data as it
365 requires for drawing the graph. If you \texttt{SHIFT} the data, you
366 may want to adjust the data fetched accordingly.}
368 \mode<article>{\newpage}
369 \section{Revers Polish Notation (RPN) Math}
371 \mode<article>{RRDtool lets you apply math operations to the data
372 prior to showing it to the user. It uses RPN math for this. If you
373 ever owned a classic HP calculator, you may still remember how RPN
374 math works. For all the others there is a little example below,
375 that shows how to do a little addition in RPN.}
377 \begin{frame}[fragile]{RPN basics: Step 0}
378 $15+23=38$
379 \begin{alltt}
380 1: NAN
381 2: NAN
382 3: NAN
383 \end{alltt}
384 \end{frame}
385 \begin{frame}[fragile]{RPN basics: Step 1}
386 $\mathbf{15}+23=38$
387 \begin{alltt}
388 [15] 1: \textbf{15}
389 2: NAN
390 3: NAN
391 \end{alltt}
392 \end{frame}
393 \begin{frame}[fragile]{RPN basics: Step 2}
394 $15+\mathbf{23}=38$
395 \begin{alltt}
396 [23] 1: \textbf{23}
397 2: 15
398 3: NAN
399 \end{alltt}
400 \end{frame}
401 \begin{frame}[fragile]{RPN basics: Step 3}
402 $15\mathbf{+}23=38$
403 \begin{alltt}
404 [+] 1: \textbf{38}
405 2: NAN
406 3: NAN
407 \end{alltt}
408 \end{frame}
411 \begin{frame}{math in the graph (+)}
412 \addgraph{RPN-simple}
413 \end{frame}
415 \mode<article>{A simple addition. We add a fixed value to a data
416 source. Note that at least one data source must appear inside a CDEF
417 expression. The input to a CDEF expression can come from another
418 CDEF expression.}
420 \begin{frame}{the MAX function}
421 \addgraph{RPN-max}
422 \end{frame}
424 \mode<article>{The MAX function operates on two values. In this example
425 the input comes from two different data sources.}
427 \begin{frame}{the LIMIT function}
428 \addgraph{RPN-limit}
429 \end{frame}
431 \mode<article>{The \texttt{LIMIT} function will return UNKNOWN as soon
432 as the input value is outside the given range. UNKNOWN data does not
433 get drawn.}
435 \begin{frame}{the TREND function}
436 \addgraph{RPN-trend}
437 \end{frame}
439 \mode<article>{If a data source varies massively, the TREND function
440 lets you smooth away by building a moving average. By calculating
441 the average, the output gets shifted by the length of the TREND
442 calculation.}
444 \begin{frame}{the TREND with early start}
445 \addgraph{RPN-trend-start}
446 \end{frame}
448 \mode<article>{In the previous graph there was a bit of data missing
449 at the left border of the graph. This was because rrdgraph loads
450 exactly the amount of data that is required in the graph (yes same
451 story as before). By loading more data, we can provide the TREND
452 function with enough input, so that it can calculate the first few
453 pixels as well.}
455 \mode<article>{\newpage}
457 \begin{frame}{the TREND and SHIFT}
458 \addgraph{RPN-trend-shift}
459 \end{frame}
461 \mode<article>{Another interesting option is to SHIFT the result of
462 the TREND calculation back in time, so that it matches with the
463 source data. This allows us to see more easily when there are
464 'outliners'}
466 \mode<article>{\newpage}
469 \begin{frame}{the IF function}
470 \addgraph{RPN-if}
471 \end{frame}
473 \mode<article>{The IF function requires three items on the stack. It
474 turns \texttt{a,b,c,IF} into \texttt{if a then b else c}. There is a
475 bunch of operators that go along with the \texttt{IF}: \texttt{LT}
476 less, \texttt{LE} - less or equal, \texttt{EQ} - equal, \texttt{NE}
477 not equal, \texttt{GE} - greater or equal, \texttt{GT} - greater.}
479 \begin{frame}{about invisibility}
480 \addgraph{RPN-UNKN}
481 \end{frame}
483 \mode<article>{Unknown values are not drawn on the graph. Here we
484 use trick to only show the largest values.}
486 \begin{frame}{positional drawing count}
487 \addgraph{RPN-count}
488 \end{frame}
490 \mode<article>{If you are into bar charts, you might fake them with
491 this trick. COUNT, counts the values of the data set. We use this,
492 together with the modulo operator to suppress the drawing of every
493 third entry.}
495 \begin{frame}{access the previous value}
496 \addgraph{RPN-prev}
497 \end{frame}
499 \begin{frame}{positional drawing time}
500 \addgraph{RPN-time}
501 \end{frame}
503 \begin{frame}{positional drawing time-shifting}
504 \addgraph{RPN-time-minus}
505 \end{frame}
507 \mode<article>{There is also a function for accessing the Unix time
508 (seconds since 1970) associated with the graph data. With it, you
509 can make your stripes a fixed number of seconds wide.}
511 \begin{frame}{time and resolution issues}
512 \addgraph{RPN-time-odd}
513 \end{frame}
515 \mode<article>{\newpage}
517 \mode<article>{Whenever RRDtool graph has to do math with data sets
518 that come in different step sizes, it first to adjust the step sizes
519 so that they match. To do this, it finds the greatest common divisor
520 and uses it as the new step size.}
522 \begin{frame}[fragile]{CDEF internals}
523 \begin{itemize}
524 \item data may come in different resolutions
525 \item all items in a CDEF must have the same resolution
526 \item resolution is expanded to greatest common devisor (gcd)
527 \item example: gcd(6,9) = 3, gcd(1,6) = 1
528 \end{itemize}
530 trick: an rrd with one a second step.
531 \begin{alltt}
532 rrdtool create one.rrd --step=1
533 DS:one:GAUGE:2:U:U
534 RRA:AVERAGE:0.5:1:1
535 \end{alltt}
536 \end{frame}
538 \begin{frame}{step=1 trick: high resolution cdef}
539 \addgraph{RPN-time-odd-hires}
540 \end{frame}
542 \mode<article>{By introducing this special rrd with a ``one second
543 step'' the greatest common divisor (gcd) becomes one.}
545 \section{Consolidation functions}
547 \begin{frame}{finding the average}
548 \addgraph{VDEF-average}
549 \end{frame}
551 \begin{frame}{calculating min and max}
552 \addgraph{VDEF-minmax}
553 \end{frame}
556 \mode<article>{\newpage}
558 \begin{frame}[fragile]{min max code example}
559 \begin{alltt}
560 LINE:a#456:a
561 VDEF:max=a,MAXIMUM
562 LINE:max#123
563 VRULE:max#123:maximum
564 GPRINT:max:%.1lf
565 GPRINT:max:%H\(\backslash\):%M\textbf{:strftime}
566 \end{alltt}
567 A VDEF result has a value and a time assigned.
568 \end{frame}
570 \begin{frame}{Least Squares Line (y=x*m+b)}
571 \addgraph{VDEF-lsl}
572 \end{frame}
575 \mode<article>{\newpage}
576 \section{Holt Winters Aberrant Behaviour Detection}
578 \begin{frame}{about alert generation}
579 \begin{itemize}
580 \item when something unexpected happens send an alert\pause
581 \item fixed thresholds are too wide a net\pause
582 \item moving averages weigh all data equal\pause
583 \item holt winters can predict the future\pause
584 \item and no one considers himself clever enough to use it
585 \end{itemize}
586 \end{frame}
588 \begin{frame}{rrd - holt winters assumptions}
589 \begin{itemize}
590 \item data is periodic in nature
591 \item data has continuity
592 \item data continuity is periodic
593 \item recent data is more important
594 \end{itemize}
595 \end{frame}
597 \begin{frame}{holt winters aberrant behavior}
598 \begin{itemize}
599 \item prediction of future value and confidence band
600 \item confidence band is like a standard deviation
601 \item real value compared to predicted value +/- confidence band
602 \end{itemize}
603 \end{frame}
605 \mode<article>{With holt winters RRDtool will calculate a prediction
606 and a confidence band (think of it as a standard deviation) for the
607 current value. It will then compare the prediction with the
608 actual value. If the actual value falls outside the confidence band
609 of the predicted value (or some multiple of it), then a confidence
610 band violation is registered. If multiple violations are registered
611 within a configurable interval, RRDtool logs a failure.}
613 \begin{frame}<presentation>{holt winters configuration}
614 \begin{itemize}
615 \item HWPREDICT for starters
616 \item tweaking required
617 \item know the knobs to turn
618 \item use real data to test
619 \item FAILURES very short
620 \item \texttt{rrdtool tune} and \texttt{resize}
621 \end{itemize}
622 \end{frame}
624 \mode<article>{
625 \begin{itemize}
626 \item Keep it simple, go for HWPREDICT only when you start using
627 holt winters in RRDtool.
628 \item Every data set is different, tweaking is required.
629 \item Know which knobs to turn.
630 \item Use real data when experimenting.
631 \item Use \texttt{rrdtool tune} to tweak settings.
632 \item The FAILURES RRA is short!
633 \end{itemize}
634 }
636 \begin{frame}{holt winters parameters}
637 \texttt{RRA:HWPREDICT:}\emph{rows}\texttt{:}\emph{alpha}\texttt{:}\emph{beta}\texttt{:}\emph{period}
639 \begin{description}
640 \item[\emph{alpha}:] adaption rate of the baseline (1 fast, 0 slow)
641 \item[\emph{beta}:] adaption rate of the slope (1 fast, 0 slow)
642 \item[\emph{period}:] how many steps in a period (use 1 to disable)
643 \item[\emph{gamma}:] seasonal adaption rate of the baseline\\(alpha by
644 default)
645 \item[\emph{dev\_gamma}:] seasonal adaption rate of the confidence
646 band\\
647 (gamma by default)
648 \end{description}
650 the gamma and confidence band are tunable with \texttt{rrdtool tune}
651 \end{frame}
653 \mode<article>{
654 Reading \href{http://cricket.sourceforge.net/aberrant/lisa2000_paper.pdf}{Brutlag's original paper}
655 I wrote down the formulas he uses for calculating holt winters. This
656 helped me quite a lot in understanding the relationships between
657 alpha, beta, gamma and delta.}
659 \begin{frame}[fragile]{the rrdtool holt winters formula}
660 \begin{small}
661 \begin{alltt}
662 a - baseline (RRA CDP Parameter)
663 b - slope (RRA CDP Parameter)
664 c - seasonal (SEASONAL RRA)
665 d - deviation (DEVSEASONAL RRA)
666 pred - predicted value
667 real - real value\pause
669 pred\{next\} = a\{now\} + b\{now\} + c\{next_prev_period\}\pause
671 a\{now\} = alpha * (real\{now\} - c\{now_prev_period\})
672 + (1-alpha) * ( a\{prev\} + b\{prev\})\pause
673 b\{now\} = beta * (a\{now\} - a\{prev\})
674 + (1-beta) * b_prev\pause
675 c\{now\} = gamma * (real\{now\} - a\{now\})
676 + (1-gamma) * c\{now_prev_period\}\pause
677 d\{now\} = dev_gamma * abs(real\{now\} - pred\{now\})
678 + (1-dev_gamma) * d\{now_prev_period\}\pause
680 \end{alltt}
681 \end{small}
682 \end{frame}
684 % must be formatted like that
685 % to break gobbling mode!
686 %\mode
687 %<all>
689 \begin{frame}{hw demo: the test data}
690 \addgraph{HW-input}
692 traffic at a peering point
693 \end{frame}
695 \begin{frame}[fragile]{drawing a hw graph}
696 \begin{lstlisting}[language=xml]
697 DEF:in=hw.rrd:in:AVERAGE
698 DEF:pred=hw.rrd:in:HWPREDICT
699 DEF:conf=hw.rrd:in:DEVPREDICT
700 DEF:fail=hw.rrd:in:FAILURES
701 TICK:fail#ff8:1:Failures
702 CDEF:lowconf=pred,conf,2,*,-
703 LINE1:lowconf
704 CDEF:confwidth=conf,4,*
705 AREA:confwidth#cfc:Band:STACK
706 LINE0.1:0#3a1::STACK
707 LINE0.1:lowconf#3a1
708 LINE1:in#c00:InOctets
709 LINE1:pred#0a0:Prediction
710 \end{lstlisting}
711 \end{frame}
713 \mode<article>{For starters we set the period to 1. This disables HW's
714 ability to adjust to periodic behavior in the data but it lets us
715 better observe the effects of the different parameter settings since
716 the adjustment period is much shorter.}
718 \begin{frame}{hw demo: alpha}
719 \addgraph{HW-p1-a0_5-b0_001}\\
720 \addgraph{HW-p1-a0_1-b0_001}
721 \end{frame}
723 \mode<article>{The smaller the alpha the slower the adaption. As the
724 prediction is now generally off by quite a bit, this causes the
725 confidence band to grow as well.}
727 \mode<article>{\newpage}
729 \begin{frame}{hw demo: beta}
730 \addgraph{HW-p1-a0_1-b0_001}\\
731 \addgraph{HW-p1-a0_1-b0_1}
732 \end{frame}
734 \mode<article>{The larger the beta the `heavier' the prediction
735 becomes.}
737 \begin{frame}{hw demo: period}
738 \addgraph{HW-p1-a0_5-b0_001}\\
739 \addgraph{HW-p48-a0_5-b0_001}
740 \end{frame}
742 \begin{frame}{hw demo: tuning}
743 \addgraph{HW-p48-a0_5-b0_001}\\
744 \addgraph{HW-p48-a0_2-b0_001}
745 \end{frame}
747 \begin{frame}{hw demo: tuning II}
748 \addgraph{HW-p48-a0_2-b0_001}\\
749 \addgraph{HW-p48-a0_03-b0_001}
750 \end{frame}
752 \begin{frame}{hw demo: tuning II}
753 \addgraph{HW-p48-a0_03-b0_001}\\
754 \addgraph{HW-p48-a0_03-b0_1}
755 \end{frame}
757 \section{Real Live Example}
759 \mode<article>{The following example shows how to create a simple
760 traffic grapher with a shell script for data acquisition, and an
761 rrdcgi script to draw the graphs.}
763 \begin{frame}
764 \includegraphics[width=\textwidth]{traffic/codewalk}
765 \end{frame}
767 \begin{frame}[allowframebreaks]{data acquisition}
768 \lstinputlisting[language=bash]{traffic/ifbyteget.sh}
769 \end{frame}
771 \mode<article>{This little bash script polls the network traffic
772 counter from the linux proc tree and reformats it so that it can be
773 fed to rrdtool.}
775 \begin{frame}[allowframebreaks]{rrdcgi: scripting for the poor}
776 \lstinputlisting[language=xml]{traffic/index.cgi}
777 \end{frame}
779 \begin{frame}[allowframebreaks]{rrdcgi: include file function}
780 \lstinputlisting[language=xml]{traffic/graph.inc}
781 \end{frame}
783 \mode<article>{RRDtool's rrdcgi is a very simple scripting engine, that can pick
784 up pseudo xml elements from an html file and execute the
785 coresponding rrdtool commands. In this example we use environment
786 variables and an include file to save us from typing in the same
787 graph definition over and over again.}
789 \mode<presentation>{
790 \begin{frame}
791 \begin{center}
792 \Huge ?
793 \end{center}
794 \end{frame}
795 \begin{frame}
796 \begin{center}
797 Tobi Oetiker <tobi@oetiker.ch>
798 \end{center}
799 \end{frame}
800 }
802 \mode<article>{
803 \vspace{\stretch{1}}
804 Tobias Oetiker <tobi@oetiker.ch>
805 }
806 \end{document}
807 %%% Local Variables:
808 %%% TeX-master: "presentation.tex"
809 %%% mode: flyspell
810 %%% TeX-PDF-mode: t
811 %%% End: