[rrd-users] Re: How to move old data into rrd

Alex van den Bogaerdt alex at ergens.op.het.net
Thu Apr 13 01:17:43 MEST 2006

On Wed, Apr 12, 2006 at 02:08:44PM -0800, Colht, Charles wrote:
> I have a lot of performance data in flat files that I would like to
> move to rrds. But when I try to use update to put the data in,
> rrdtool complains about the old time stamps or the interval
> (I'm feeding it lots 5 minute data points per second.) Is
> there any way to do this?

Always submit data in sequence.  You cannot go back in time.  And of
course you need to use specific time stamps, not "N" for "now".

An easy way to accomplish this is to sort your data.  Time stamps
are in front.  Unless your data was collected before september 9,
2001, 01:46:40 UTC, time stamps are all 10 characters wide and
sorting will be a no brainer.

Also, you cannot have two updates at the same time.

You need to update all datasources in an RRD at the same time,
i.e. do not do:

rrdtool update my.rrd 1104537600:1
rrdtool update my.rrd 1104537600::2
rrdtool update my.rrd 1104537600:::3

but do

rrdtool update my.rrd 1104537600:1:2:3

If that means you need to preprocess your input, it means you need
to preprocess your input.

If you already have an RRD containing recent data, you cannot easely
"prepend" data (rrdtool doesn't work that way).  What you can do is
generate a new database using exactly the same properties as your
current database, make sure both databases are updated at the same
time (supplying the current data to both databases) and merge them
using whatever method you prefer.  Search the archives for detailed

In my experience, this usually is doable.
Alex van den Bogaerdt

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