clearing crc error counter on switch leads to huge numbers in crc error graph

edited August 2016 in SAN
Hi, we just cleared the crc error counter on a switch, and it seems that stor2rrd misinterprets the negative number (calculated "current errors=0" - "number of last errors before clearing>0") as integer (and not as unsigned integer or something like that). The graph showed us a huge number for the crc errors (millions). I think if the result is a negative number it should be set to 0 by stor2rrd.


  • edited July 2016

    this might happen if you clear the counter, there is no way which would avoid it completly if this happens.

    use this method to clean the peak out.
    get script, gunzip and copy to /home/stor2rrd/stor2rrd,

    Usage example is for SAN switch ASAN11 and port 14 (note file has index 15 if you use stor2rrd 1.30, for lower stor2rrd use 14) : data/ASAN11/port15.rrd
    Column name is: swFCPortRxCrcs
    data limit 1000 (peaks higher than 1000 errors per seconds will be removed)

    # su - stor2rrd
    $ cd /home/stor2rrd/stor2rrd
    $ ksh ./
    Provide full path to RRDTool file

    Provide column name

    Provide data limit

    Working for: data/ASAN11/port15.rrd:swFCPortRxCrcs and limit 1000
    Actual MAX limit of that item in RRDTool file is:
    Load has been done with MAX limit: 1.0000000000e+03

    I hope it is clear and will work for you :)

  • Hi Pavel,

    thanks for the quick reply - yes, this works for me, thanks!

    Just thought there might be a way to avoid those peaks all together...
  • It is hard to avoid such peaks when the source is type counter.
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