trace_rpc_histD6<\/a> (sorry it’s a docx file containing the content of the awk scripts as I cannot upload an awk or txt or zip file into our blog but docx is allowed, somehow…?)<\/em><\/p>\nAs you can see above, it is not really maintained and the same scripts or a mix of several versions can be found at several locations so it can be a little bit confusing. All the old links are about the awk scripts but since 2013, there is now a python script too (also developed by Ed Bueche).<\/p>\n
In this blog, I wanted to talk about the AWK scripts mainly. Earlier this month, I was working with OTX on some performance tuning tasks and for that, I gathered the DFC traces for several scenarios, in different log files, well separated, aso… Then, I provided them to OTX for the analysis. OTX came back to me a few minutes later saying that most of the traces were corrupted and asking me to regenerate them. Since it takes time and because there were some testing in progress on this environment, then gathering clean DFC traces for several scenarios would have forced the tests to be stopped, aso… So if possible, I wanted to avoid doing that. (Ok ok you got me, I’m just lazy ;))<\/p>\n
The content of the DFC traces looked correct to me and after a quick verification, I saw that OTX was trying to use the AWK scripts (traceD6.awk and trace_rpc_histD6.awk) to analyze the logs but they were apparently getting an error. The files didn’t look corrupted to me so I mentioned to OTX that the issue might very well be with the AWK scripts they were using. They weren’t really convinced about that so I decided to take a look at these scripts and try to find it out. I already used these scripts but never really looked inside so it was the perfect opportunity<\/span><\/span> to take some time for that:<\/p>\n\n
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\n\n\n\n1<\/div>\n 2<\/div>\n 3<\/div>\n 4<\/div>\n 5<\/div>\n 6<\/div>\n 7<\/div>\n 8<\/div>\n 9<\/div>\n 10<\/div>\n 11<\/div>\n 12<\/div>\n 13<\/div>\n 14<\/div>\n 15<\/div>\n 16<\/div>\n 17<\/div>\n 18<\/div>\n 19<\/div>\n 20<\/div>\n<\/td>\n \n\n [dmadmin@content_server_01 ~]$ <\/code>cd<\/code> \/tmp\/dfc_tracing\/<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$ <\/code>ls<\/code> -l trace* dfctrace.*.log<\/code><\/div>\n-rw-r-----. 1 dmadmin dmadmin 92661060 Nov 3 09:24 dfctrace.1510220481672.log<\/code><\/div>\n-rw-r-----. 1 dmadmin dmadmin 3240 Nov 4 14:10 traceD6.<\/code>awk<\/code><\/div>\n-rw-r-----. 1 dmadmin dmadmin 7379 Nov 4 14:10 traceD6.py<\/code><\/div>\n-rw-r-----. 1 dmadmin dmadmin 5191 Nov 4 14:10 trace_rpc_histD6.<\/code>awk<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$ <\/code>awk<\/code> -f traceD6.<\/code>awk<\/code> < dfctrace.1510220481672.log > output_awk_1.log<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$ <\/code>wc<\/code> -l output_awk_1.log<\/code><\/div>\n2 output_awk_1.log<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$ <\/code>awk<\/code> -f trace_rpc_histD6.<\/code>awk<\/code> < dfctrace.1510220481672.log > output_awk_2.log<\/code><\/div>\nawk<\/code>: trace_rpc_histD6.<\/code>awk<\/code>:203: (FILENAME=- FNR=428309) fatal: division by zero attempted<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$ <\/code>wc<\/code> -l output_awk_2.log<\/code><\/div>\n4 output_awk_2.log<\/code><\/div>\n[dmadmin@content_server_01 dfc_tracing]$<\/code><\/div>\n<\/div>\n<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\nAs you can see above, the first script generated a log file that contains only 2 lines, so this is already suspicious even if there are no errors. The second script generated an error and its log file contains only 4 lines… The input DFC trace file has a size of 90Mb so it’s clear that there is something wrong and that’s why OTX said that the DFC traces were corrupted. The error message shows the line (203) as the origin of the issue as well as a “division by zero attempted” message. This obviously means that somewhere on this line, there is a division and that the divisor is equal to 0 or at least not set at all. Since I love all kind of UNIX scripting, I would rather fix the bug in the script than having to generate a new set of DFC traces (and the new set would still be impacted by the issue anyway…)! So checking inside the trace_rpc_histD6.awk file, the line 203 is the following one:<\/p>\n \n \n \n\n\n\n1<\/div>\n 2<\/div>\n 3<\/div>\n 4<\/div>\n 5<\/div>\n<\/td>\n \n\n [dmadmin@content_server_01 dfc_tracing]$ <\/code>
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