@@ -77,71 +84,76 @@ further down. There is also a number of language bindings for RRDtool which allow you to use it directly from Perl, python, Tcl, PHP, etc.
Set up a new Round Robin Database (RRD). Check the rrdcreate manpage.
Store new data values into an RRD. Check the rrdupdate manpage.
Operationally equivalent to update except for output. Check the rrdupdate manpage.
Create a graph from data stored in one or several RRDs. Apart from generating graphs, data can also be extracted to stdout. Check the rrdgraph manpage.
Dump the contents of an RRD in plain ASCII. In connection with restore you can use this to move an RRD from one computer architecture to another. Check the rrddump manpage.
Restore an RRD in XML format to a binary RRD. Check the rrdrestore manpage
Get data for a certain time period from a RRD. The graph function uses fetch to retrieve its data from an RRD. Check the rrdfetch manpage.
Alter setup of an RRD. Check the rrdtune manpage.
Find the last update time of an RRD. Check the rrdlast manpage.
Get information about an RRD. Check the rrdinfo manpage.
Change the size of individual RRAs. This is dangerous! Check the rrdresize manpage.
Export data retrieved from one or several RRDs. Check the rrdxport manpage
+Export data retrieved from one or several RRDs. Check the rrdxport manpage.
Flush the values for a specific RRD file from memory. Check the rrdflushcached manpage.
+This is a standalone tool for producing RRD graphs on the fly. Check @@ -152,7 +164,7 @@ uses fetch to retrieve its data from an RRD. Check t
When monitoring the state of a system, it is convenient to have the @@ -165,7 +177,7 @@ interpolated value to the log. The original value you have supplied is stored as well and is also taken into account when interpolating the next log entry.
You may log data at a 1 minute interval, but you might also be @@ -182,7 +194,7 @@ consolidated values (see rrdcreate). You can define any number of different consolidation setups within one RRD. They will all be maintained on the fly when new data is loaded into the RRD.
Data values of the same consolidation setup are stored into Round @@ -209,7 +221,7 @@ exactly the type of information that actually interests you: the maximum one minute traffic on the LAN, the minimum temperature of your wine cellar, the total minutes of down time, etc.
As mentioned earlier, the RRD stores data at a constant @@ -225,7 +237,7 @@ performed to make sure that the percentage of unknown values in the data point is above a configurable level. If not, an *UNKNOWN* value will be written to the RRA.
RRDtool allows you to generate reports in numerical and @@ -234,7 +246,7 @@ graphical form based on the data stored in one or several contents of the graph can be defined freely. Check the rrdgraph manpage for more information on this.
by Jake Brutlag
@@ -261,7 +273,7 @@ a time series. Its forecast is the sum of three components: a baseline coefficient (a periodic effect, such as a daily cycle). There is one seasonal coefficient for each time point in the period (cycle). After a value is observed, each of these components is updated via -exponential smoothing. This means that the algorithm ``learns'' from +exponential smoothing. This means that the algorithm "learns" from past values and uses them to predict the future. The rate of adaptation is governed by 3 parameters, alpha (intercept), beta (slope), and gamma (seasonal). The prediction can also be viewed as a @@ -333,8 +345,17 @@ such a port unless you are sure what you are doing.
For very big setups, updating thousands of RRD files often becomes a serious IO +problem. If you run into such problems, you might want to take a look at +the rrdcached manpage, a caching daemon for RRDTool which may help you lessen the +stress on your disks.
++
+rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrdtune, rrdlast, rrdxport
+rrdcreate, rrdupdate, rrdgraph, rrddump, rrdfetch, rrdtune, rrdlast, rrdxport, +rrdflushcached, rrdcached