element. As we are on a circle there is no beginning nor an end, you can
go on and on. After a while, all the available places will be used and
the process automatically reuses old locations. This way, the database
-will not grow in size and therefore requires no mainenance.
+will not grow in size and therefore requires no maintenance.
RRDtool works with with Round Robin Databases (RRDs). It stores and retrieves
data from them.
and process data collected via SNMP. The data will most likely be bytes
(or bits) transfered from and to a network or a computer.
RRDtool lets you create a database, store data in it, retrieve that data
-and create graphs in GIF format for display on a web browser. Those GIF
+and create graphs in PNG format for display on a web browser. Those PNG
images are dependent on the data you collected and could be, for instance,
an overview of the average network usage, or the peaks that occurred.
It can also be used to display tidal waves, solar radiation, power
and it tells you that the car has moved 12345 KM until that moment.
At 12:10 you look again, it reads 12357 KM. This means you have
traveled 12 KM in five minutes. A scientist would translate that
-into meters per second and this makes a nice comparison towards the
+into meters per second and this makes a nice comparison toward the
problem of (bytes per five minutes) versus (bits per second).
We traveled 12 kilometers which is 12000 meters. We did that in five
Try the following command:
- rrdtool graph speed.gif \
+ rrdtool graph speed.png \
--start 920804400 --end 920808000 \
DEF:myspeed=test.rrd:speed:AVERAGE \
LINE2:myspeed#FF0000
-This will create speed.gif which starts at 12:00 and ends at 13:00.
+This will create speed.png which starts at 12:00 and ends at 13:00.
There is a definition of variable myspeed, it is the data from RRA
"speed" out of database "test.rrd". The line drawn is 2 pixels high,
and comes from variable myspeed. The color is red.
magenta #FF00FF (mixed red with blue)
gray #555555 (one third of all components)
-The GIF you just created can be displayed using your favorite image
-viewer. Web browsers will display the GIF via the URL
-"file://the/path/to/speed.gif"
+The PNG you just created can be displayed using your favorite image
+viewer. Web browsers will display the PNG via the URL
+"file://the/path/to/speed.png"
=head2 Graphics with some math
Let's correct that. We could recreate our database and store the correct
data but there is a better way: do some calculations while creating the
-gif file !
+png file !
- rrdtool graph speed2.gif \
+ rrdtool graph speed2.png \
--start 920804400 --end 920808000 \
--vertical-label m/s \
DEF:myspeed=test.rrd:speed:AVERAGE \
- CDEF:realspeed=myspeed,1000,* \
+ CDEF:realspeed=myspeed,1000,\* \
LINE2:realspeed#FF0000
-After viewing this GIF, you notice the "m" has disappeared. This it what
+After viewing this PNG, you notice the "m" has disappeared. This it what
the correct result would be. Also, a label has been added to the image.
-Apart from the things mentioned above, the GIF should be the same.
+Apart from the things mentioned above, the PNG should be the same.
The calculations are in the CDEF part and are in Reverse Polish Notation
("RPN"). What it says is: "take the data source myspeed and the number
this by multiplying with 1000. Applying that correction:
-*- value * 3.6 *1000 == value * 3600
-Now let's create this GIF, and add some more magic ...
+Now let's create this PNG, and add some more magic ...
- rrdtool graph speed3.gif \
+ rrdtool graph speed3.png \
--start 920804400 --end 920808000 \
--vertical-label km/h \
DEF:myspeed=test.rrd:speed:AVERAGE \
I like to believe there are virtually no limits to how RRDtool graph
can manipulate data. I will not explain how it works, but look at the
-following GIF:
+following PNG:
- rrdtool graph speed4.gif \
+ rrdtool graph speed4.png \
--start 920804400 --end 920808000 \
--vertical-label km/h \
DEF:myspeed=test.rrd:speed:AVERAGE \
AREA:fast#550000:"Too fast" \
STACK:over#FF0000:"Over speed"
-Let's create a quick and dirty HTML page to view three GIFs:
+Let's create a quick and dirty HTML page to view three PNGs:
<HTML><HEAD><TITLE>Speed</TITLE></HEAD><BODY>
- <IMG src="speed2.gif" alt="Speed in meters per second">
+ <IMG src="speed2.png" alt="Speed in meters per second">
<BR>
- <IMG src="speed3.gif" alt="Speed in kilometers per hour">
+ <IMG src="speed3.png" alt="Speed in kilometers per hour">
<BR>
- <IMG src="speed4.gif" alt="Traveled too fast?">
+ <IMG src="speed4.png" alt="Traveled too fast?">
</BODY></HTML>
Name the file "speed.html" or similar, and view it.
Now, all you have to do is measure the values regularly and update the
-database. When you want to view the data, recreate the GIFs and make
+database. When you want to view the data, recreate the PNGs and make
sure to refresh them in your browser. (Note: just clicking reload may
not be enough; Netscape in particular has a problem doing so and you'll
need to click reload while pressing the shift key).
understand yet, you should be able to find out how to start the
program and use it.
- snmpget myrouter public system.sysdescr.0
+ snmpget myrouter public system.sysDescr.0
The device should answer with a description of itself, perhaps empty.
Until you got a valid answer from a device, perhaps using a different
"password", or a different device, there is no point in continuing.
- snmpget myrouter public interfaces.ifnumber.0
+ snmpget myrouter public interfaces.ifNumber.0
Hopefully you get a number as a result, the number of interfaces.
If so, you can carry on and try a different program called "snmpwalk".
- snmpwalk myrouter public interfaces.iftable.ifentry.ifdescr
+ snmpwalk myrouter public interfaces.ifTable.ifEntry.ifDescr
If it returns with a list of interfaces, you're almost there.
Here's an example:
Then, after collecting data for a day, try to create an image using:
- rrdtool graph myrouter-day.gif --start -86400 \
+ rrdtool graph myrouter-day.png --start -86400 \
DEF:inoctets=myrouter.rrd:input:AVERAGE \
DEF:outoctets=myrouter.rrd:output:AVERAGE \
AREA:inoctets#00FF00:"In traffic" \
get a totally different picture. You would see the same values on the
average and maximum graphs (provided I measured every 300 seconds).
You would be able to see when I stopped, when I was in top gear, when
-I drove over fast hiways etc. The granularity of the data is much
+I drove over fast highways etc. The granularity of the data is much
higher, so you can see more. However, this takes 12 samples per hour,
or 288 values per day, so it would be too much to keep for a long
period of time. Therefore we average it, eventually to one value per
so called hot-spot and the exhaust. These values are not counters.
If I take the difference of the two samples and divide that by
300 seconds I would be asking for the temperature change per second.
-Hopefully this is zero! If not, the computerroom is on fire :)
+Hopefully this is zero! If not, the computer room is on fire :)
So, what can we do ? We can tell RRDtool to store the values we measure
directly as they are (this is not entirely true but close enough). The
978303300:2400:6:600:2400 \
978303600:2700:4:600:2700 \
978303900:3000:2:1200:3000
- rrdtool graph all1.gif -s 978300600 -e 978304200 -h 400 \
+ rrdtool graph all1.png -s 978300600 -e 978304200 -h 400 \
DEF:linea=all.rrd:a:AVERAGE LINE3:linea#FF0000:"Line A" \
DEF:lineb=all.rrd:b:AVERAGE LINE3:lineb#00FF00:"Line B" \
DEF:linec=all.rrd:c:AVERAGE LINE3:linec#0000FF:"Line C" \
=item *
-Line B is of type gauge. These are "real" values so they should match
+Line B is of type GAUGE. These are "real" values so they should match
what we put in: a sort of a wave.
=item *
- Line C: u u 2 2 2 0 -2 -6 2 0 2 u
- Line D: u 1 2 3 4 5 6 7 8 9 10 u
-If your GIF shows all this, you know you have typed the data correct,
+If your PNG shows all this, you know you have typed the data correct,
the RRDtool executable is working properly, your viewer doesn't fool you
and you successfully entered the year 2000 :)
You could try the same example four times, each time with only one of
rrdtool update seconds2.rrd \
920805000:000 920805300:300 920805603:603 920805900:900
- rrdtool graph seconds1.gif \
+ rrdtool graph seconds1.png \
--start 920804700 --end 920806200 \
--height 200 \
--upper-limit 1.05 --lower-limit 0.95 --rigid \
CDEF:unknown=seconds,UN \
LINE2:seconds#0000FF \
AREA:unknown#FF0000
- rrdtool graph seconds2.gif \
+ rrdtool graph seconds2.png \
--start 920804700 --end 920806200 \
--height 200 \
--upper-limit 1.05 --lower-limit 0.95 --rigid \
projects / rrdtool.git / blobdiff