[rrd-users] Can I stuff an RRD with data after-the-fact?

Simon Hobson linux at thehobsons.co.uk
Wed Sep 17 08:59:06 CEST 2014

On 16 Sep 2014, at 19:17, Alan McKay <alan.mckay at gmail.com> wrote:

> On Tue, Sep 16, 2014 at 11:00 AM, Simon Hobson <linux at thehobsons.co.uk> wrote:
>> That will work just fine *IF* none of the data in your file is older than data in the RRD file AND all the timestamps in the file are in increasing order. With each update, the RRD will update just the same as if you'd fed them in in real time as the data was collected.
> Well I only wrote this because it did not seem to work at all.  It was
> a fresh RRD - newly created.  And timestamps were increasing.

As already mentioned, you can specify the start time for an RRD when it's created - the default is "now".

>> Lastly, have you considered using rrdcached ? Collect the data on one machine, and do rrdtool updates from there specifying the cached address - the data is then transferred to the other machine and the RRD updated in real time*. It works really well for distributed data collection like this - I use it on many of my systems.
> I'll have a look at it, but in our environment any kind of extraneous
> agent or daemon can only be introduced after considerable scrutiny.
> Which is why I did not want to run rrdtool locally.  THough I'm going
> through the process to get it introduced.
> It is technically not a daemon like that, so should be good.
> Also, I can't really allow data to be pushed from a host to a collector.
> I could only pull from the collector.

Do you run Nagios (or anything similar) ? For some of my stats, I twigged that Nagios already collected some performance stats (but not all I wanted) - it just needs a bit of scripting to drop that data into a file and process it.

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