# NAME

rrdupdate - Store a new set of values into the RRD

# SYNOPSIS

rrdtool {update | updatev} filename [--template|-t ds-name[:ds-name]...] [--] N|timestamp:value[:value...] at-timestamp@value[:value...] [timestamp:value[:value...] ...]

# DESCRIPTION

The update function feeds new data values into an RRD. The data is time aligned (interpolated) according to the properties of the RRD to which the data is written.

updatev

  This alternate version of update takes the same arguments and performs the same function. The v stands for verbose, which describes the output returned. updatev returns a list of any and all consolidated data points (CDPs) written to disk as a result of the invocation of update. The values are indexed by timestamp (time_t), RRA (consolidation function and PDPs per CDP), and data source (name). Note that depending on the arguments of the current and previous call to update, the list may have no entries or a large number of entries.

filename

  The name of the RRD you want to update.

--template|-t ds-name[:ds-name]...

  By default, the update function expects its data input in the order the data sources are defined in the RRD, excluding any COMPUTE data sources (i.e. if the third data source DST is COMPUTE, the third input value will be mapped to the fourth data source in the RRD and so on). This is not very error resistant, as you might be sending the wrong data into an RRD.

  The template switch allows you to specify which data sources you are going to update and in which order. If the data sources specified in the template are not available in the RRD file, the update process will abort with an error message.

  While it appears possible with the template switch to update data sources asynchronously, RRDtool implicitly assigns non-COMPUTE data sources missing from the template the *UNKNOWN* value.

  Do not specify a value for a COMPUTE DST in the update function. If this is done accidentally (and this can only be done using the template switch), RRDtool will ignore the value specified for the COMPUTE DST.

N|timestamp:value[:value...]

  The data used for updating the RRD was acquired at a certain time. This time can either be defined in seconds since 1970-01-01 or by using the letter 'N', in which case the update time is set to be the current time. Negative time values are subtracted from the current time. An AT_STYLE TIME SPECIFICATION (see the rrdfetch documentation) may also be used by delimiting the end of the time specification with the '@' character instead of a ':'. Getting the timing right to the second is especially important when you are working with data-sources of type COUNTER, DERIVE or ABSOLUTE.

  When using negative time values, options and data have to be separated by two dashes (--), else the time value would be parsed as an option. See below for an example.

  The remaining elements of the argument are DS updates. The order of this list is the same as the order the data sources were defined in the RRA. If there is no data for a certain data-source, the letter U (e.g., N:0.1:U:1) can be specified.

  The format of the value acquired from the data source is dependent on the data source type chosen. Normally it will be numeric, but the data acquisition modules may impose their very own parsing of this parameter as long as the colon (:) remains the data source value separator.

# EXAMPLE

`rrdtool update demo1.rrd N:3.44:3.15:U:23`

Update the database file demo1.rrd with 3 known and one *UNKNOWN* value. Use the current time as the update time.

`rrdtool update demo2.rrd 887457267:U 887457521:22 887457903:2.7`

Update the database file demo2.rrd which expects data from a single data-source, three times. First with an *UNKNOWN* value then with two regular readings. The update interval seems to be around 300 seconds.

`rrdtool update demo3.rrd -- -5:21 N:42`

Update the database file demo3.rrd two times, using five seconds in the past and the current time as the update times.

# AUTHOR

Tobias Oetiker <tobi@oetiker.ch>