Expert Oracle Exadata - Parent Directory

CHAPTER 12 MONITORING EXADATA PERFORMANCEThe script goes through all the filenames, which match the second expression on the command line andgreps for whatever metric is specified as the first parameter (in double quotes). In this case we arelooking for Number of Latency Threshold Warnings for Redo Log Writes, which is incremented when I/Ooperations tagged as redolog file writes take too long to complete in the cell. Apparently there were twoI/O operations around the time range between 00:00:18 and 00:00:23 which had response times highenough to be reported.Using the previous example, you can already generate formatted data good enough for visualinspection or loading into Excel or some charting tool. If you are looking only for some random problemtimes, then you can do post-processing, such as showing just the lines where the metric value is notzero:# ./oswextract.sh "Number of latency threshold warnings for redo log writes" \enkcel03.enkitec.com_cellsrvstat_11.05.*.*.dat.bz2 | grep -v " 0 "TIME CURRENT_VAL CUMULATIVE_VALSat May 7 02:00:02 2 2Sat May 7 06:00:03 10 12Sat May 7 08:00:02 5 17Sat May 7 21:28:15 1 18Sat May 7 22:00:19 1 19Sat May 7 22:00:29 4 23Sat May 7 22:00:34 4 27Sun May 8 02:00:03 10 37Sun May 8 02:00:09 8 45Sun May 8 04:00:03 4 49Sun May 8 06:00:11 11 82Sun May 8 08:00:05 6 88Mon May 9 02:00:10 16 104Mon May 9 04:00:02 4 108Alternatively, you can sort the output by the metric value in the CURRENT_VAL column to see the worstproblem times first. The next example uses sort -nrk5 as we’re sorting the fifth column (columns 1–4are the date column components, as far as the sort utility sees):# ./oswextract.sh "Number of latency threshold warnings for redo log writes" \enkcel03.enkitec.com_cellsrvstat_11.05.*.*.dat.bz2 | \grep -v " 0 " | sort -nrk5 | headSat May 14 06:00:03 30 631Fri May 13 00:00:09 25 432Tue May 10 02:00:09 22 174Sat May 14 00:00:11 22 549Wed May 11 02:00:08 17 215Mon May 9 02:00:10 16 104Tue May 10 22:00:09 12 190Sun May 8 06:00:11 11 82Mon May 9 22:00:07 11 126Sun May 8 02:00:03 10 37Apparently, the most log file write latency problems were detected at 6:00:03 AM May 14. When you lookat the other output lines, you probably see an interesting pattern. All these problems are reported from afew seconds after a full hour. Well, this is just because in this particular Exadata testing cluster, we haveover ten separate databases installed, but they only run some reports in parallel and usually there is no416