[CentOS] Load Average

Peter Farrow peter at farrows.org
Wed Mar 1 23:26:13 UTC 2006

That works out at a load average of about 18 per cpu, which is of course 
workable as you point out, however stuff like sendmail would bulk when 
it reaches 12.


Lamar Owen wrote:
> On Wednesday 01 March 2006 13:45, Peter Farrow wrote:
>> You need to check out whether the system is waiting on  IO,  on the
>> version of top on Centos 4.2 it doesn't show IO wait on the display, but
>> on the RH enterprise shipping version it does.
>> A load average of 9 is getting high, you expect would services like
>> sendmail to stop listening once the system load average gets to 12.
> As a data point, on my Sun E6500 during load testing a few months back, under 
> Aurora SPARC Linux (I would expect similar performance from CentOS SPARC) I 
> was pulling a load average of 250+ with little interactive degradation 
> (command line mode).  The E6500 had 14 CPU's and 16GB of RAM at the time, and 
> was serving an ab load (apache bench) of 256 concurrent requests to a Koha 
> integrated library system backend, over a total of 2.5 million requests.  
> Every page hit the database at least twice, from Perl.  System at that load 
> average was serving 6 pages per second; at a concurrency of 1, system served 
> 4 pages per second, so performance increased as load did.  I would have hit 
> it with more concurrency, but httpd was compiled with a 256 connection max 
> limit.

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