rrdtool RDUPDATE(1)
NAME
rrdupdate - Store a new set of values into the RD
SYNOPSIS
rrdtool {update updatev} filename [--template-t ds-
name[:ds-name]...] Ntimestamp:value[:value...] at-
timestamp@value[:value...] [timestamp:value[:value...] ...]
DESCRIPTION
The update function feeds new data values into an RD. The
data is time aligned (interpolated) according to the
properties of the RD 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 (timet), RA (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 RD 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 RD, 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 RD and so on). This is not very error
resistant, as you might be sending the wrong data
into an RD.
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 RD file, the update process
will abort with an error message.
While it appears possible with the template switch
to update data sources asynchronously, RDtool
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),
1.3.5 Last change: 2008-03-15 1
rrdtool RDUPDATE(1)
RDtool will ignore the value specified for the
COMPUTE DST.
Ntimestamp:value[:value...]
The data used for updating the RD 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 ATSTYLE 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.
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 RA. 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.
AUTHOR
Tobias Oetiker
1.3.5 Last change: 2008-03-15 2
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