Nagios Support Forum

Posted: **Wed Aug 14, 2019 1:18 am**

Dear Expert

we have below two performance graphs (rrd.files) , Unit = M for both files (graph and MRTG word use interchangeably)

Host/Service
Directory/File
router1/Fast0_1.rrd (old graph 1Jan19 till 31Mar19)
router2/Giga0_2.rrd (new graph 1Apr19 till now)

The 100Mbps link upgraded to 1Gbps, the first MRTG is from 01-Jan-2019 till 31-Mar-2019 ,, the second graph from 1-Apr-2019 till now
we want old graph reading to be reflect to new graph (you can say how to merge both graph) , if possible old graph to be reflect to new file (or can be generate new third rrd file having old+new readings).

Regards

Posted: **Wed Aug 14, 2019 7:52 am**

**I am going to preface this by saying I have not done this so you should have a backup of all RRD files before attempting this**

I found this of the rrdtool website:
https://oss.oetiker.ch/rrdtool/pub/cont ... rrd.tar.gz

Looking at it you should be able to do the following after extracting the tarball

Code: Select all

    Usage: merge-rrd.py <old rrd> <new rrd> <merged rrd>
    
    merge-rrd.py is a python script that merges that data found in rrd
    files.  This assumes that the two rrds are have the same data structure.
    
    The script creates the merged rrd by copying the entries from the new rrd.
    If the new rrd has database entries with missing data, then the records
    of the old rrd are used instead.  This mean that data from the new rrd
    will always take precedence over the data in the old rrd.

Given that once created you could move the created <merged rrd> into the location you have the existing RRD and it should work.

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how to merge two rrd files

how to merge two rrd files

Re: how to merge two rrd files