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I read about a few articles on line, but I still do not get how logrotate works.

My config file is as follows:

/var/log/usage.log  {
  rotate 10
  daily
  size 1G

  missingok
  notifempty
  sharedscripts
  postrotate
    /usr/local/bin/cond_pkill.sh -s HUP /var/run/production.pid java
  endscript
}

I notice that my main service performance dip a little bit whenever logrotate starts. I am trying to find out the reason.

I can think of two things right now.

One is logrotate actually copies the files around instead of renaming them. Is this true? I understand that logrotate config has an option called copy. If I do not set that option, will logrotate still copy the files? My files are large, > 2G each.

Another thing is HUP signal causes my service performance to dip. I will follow up on that.

Thanks, Jerry

jerry
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    I think, your problem is not related to rotating the logs per-se. It is originating from the "kill -HUP PIDofYourProgram" part. Your application may not be designed to handle the HUP signal effectively. Without knowing your app intrinsically, it is hard to tell why the performance dips and you did not mention anything about this app of yours, as in what it is and what it does. – MelBurslan Dec 12 '12 at 22:15
  • silencedhaven, I want to understand how logrotate works to isolate the reason, but I think maybe you are right. But if logrotate really copies the files around, it will also become a bottleneck, right? – jerry Dec 12 '12 at 22:21
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    according to your conf, you should have 9 backup logs ~1 GB each in size. When you hit 1 GB limit on your current log, it deletes your oldest log, renames everything to one level older, copies the content of the current log as first level old file. Then it zeroes out the current logfile and runs a "kill -HUP" command on your PID so that it rereads the logfile and starts from scratch. mv'ing 9 files and cp'ing 1 GB file, should not cause any bottleneck in any semi-decent system. Since you are HUP'ing java code, I say, all bets are off, especially if this is a home-brew code. – MelBurslan Dec 12 '12 at 22:29
  • I am not a java expert but I have seen enough number of "professionally written" java programs, bringing systems down to their knees, my guess is, your HUP signal is not being processed by your java application properly. If you have access to the developer of the code, ask them how they handle this HUP event. – MelBurslan Dec 12 '12 at 22:32
  • silencedhaven, Thank you very much! I will follow your suggestion! – jerry Dec 12 '12 at 23:54

0 Answers0