Combined graph from two OIDs (high/low)

[shaggy62]

I'm new to the forums. If this has been covered elsewhere prior to this post, please forgive my lack of search-fu.

I'm working on graphing iSCSI stats against my NetApp filers (2050s, 3020s and 3070s)

I have all the OIDs I need identified and confirmed through NetApp support.

iscsiHighOps snmp.1.3.6.1.4.1.789.1.17.11.0
iscsiHighReadBytes snmp.1.3.6.1.4.1.789.1.17.8.0
iscsiHighWriteBytes snmp.1.3.6.1.4.1.789.1.17.10.0
iscsiIsLicensed snmp.1.3.6.1.4.1.789.1.17.2.0
iscsiLowOps snmp.1.3.6.1.4.1.789.1.17.12.0
iscsiLowReadBytes snmp.1.3.6.1.4.1.789.1.17.7.0
iscsiLowWriteBytes snmp.1.3.6.1.4.1.789.1.17.9.0


specifically, the

iscsiHighOps snmp.1.3.6.1.4.1.789.1.17.11.0
iscsiLowOps snmp.1.3.6.1.4.1.789.1.17.12.0
iscsiHighOps = The total number of iSCSI ops handled since the last boot. This object returns the most significant 32 bits of the 64 bit unsigned integer.
iscsiLowOps = The total number of iSCSI ops handled since the last boot. This object returns the least significant 32 bits of the 64 bit unsigned integer.

My question is how I go about combining the high and low values so that everything is properly displayed in the graph that I'll be creating. I'll be creating a graph template for these data sources that will be line graphs of the read, write and total ops.

Any help is appreciated.

[BSOD2600]

My guess would be create a data template which holds both the low and high values separate. Then use an rrdtool CDEF to do the math and combine them on the graph.

[shaggy62]

My guess would be create a data template which holds both the low and high values separate. Then use an rrdtool CDEF to do the math and combine them on the graph.

Thanks for that suggestion, this is what I plan to do. However, I'm stuck when creating the graph template. I've added each data source individually to the graph template. Once that's done I have 6 data sources in the graph template and would like to wind up with three unique graphed lines, one being total ops, one total read bytes and one total write bytes.

Where I'm having difficulty is where/how to add a/the CDEF that will total each set of two data sources.

[BSOD2600]

Graph Management -> CDEFs is where you add new ones.

Please read the link I already posted on what a CDEF is and how to properly create it using RPN notation.