[Deploying Sakai] Sakai Instances 100% CPU Usage

[Lance Speelmon]

Yes Beth we saw this on a relatively small number of our machines (mostly dev and test machines).  The machines that were unaffected are running:

Linux 2.6.35.14-106.53.amzn1.x86_64 #1 SMP x86_64 GNU/Linux
Linux 3.2.12-3.2.4.amzn1.x86_64 #1 SMP x86_64 GNU/Linux

L

On Jul 3, 2012, at 8:22 AM, Beth Kirschner <bkirschn at umich.edu> wrote:

> There was a leap second this weekend (June 30, 8pm EDT) which we believe caused all our servers to hit 100% CPU usage simultaneously. Has anyone else in the Sakai community seen this? We're running:
> 	Linux 2.6.32-220.17.1.el6.x86_64 
> 	java version "1.6.0_22" 
> 
> Thanks,
> - Beth
> 
> Begin forwarded message:
>> 
>> 
>> 
>> URL = http://wiki.os-ux.com/java-leap-second-bug-30-june-1-july-2012-fix/
>> 
>> 
>> 
>> java leap second bug – 30 June / 1 July 2012 – fix
>> If your java applications suddenly started to use 100% CPU, you’ve hit java leap second bug (actually it’s a bug in Linux kernel, just java programs seem to be severely affected).
>> 
>> First, you may check if you have the following in your dmesg:
>> 
>> 
>> [10703552.860274] Clock: inserting leap second 23:59:60 UTC
>> 
>> Fortunately the fix is straightforward:
>> 
>> /etc/init.d/ntpd stop
>> date -s "$(date)"
>> 
>> /etc/init.d/ntpd start
>> 
>> (the other suggested way around the web would be date `date +"%m%d%H%M%C%y.%S"`, having the same effect).
>> 
>> You don’t have to restart your java applications (tomcat, solr, wowza, or whatever using java); it should be enough to run the above commands.
>> 
>> You may want to enable ntp the next day (there were some reports that enabling it makes java misbehave on some installations).
>> 
>> Apparently this issue has knocked down lots of Linux servers running Debian, Ubuntu, CentOS and the like around the globe!
>> 
>>  read more
>> 
>> (via wpkg.org)
>> 
>> Author: Vucomir Ianculov on July 3, 2012 
>> Category: Linux / Unix 
>> Tags: date, java, kernel, linux, ntpd, Zimbra
>>  
>> 
> 
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