[LON-CAPA-dev] Viewing Student sequences/Access Servers

Scott Harrison lon-capa-dev@mail.lon-capa.org
Fri, 08 Feb 2002 09:25:59 -0500

Some unofficial answers:

Mark Lucas wrote:
> (2) When setting up a second access server, load balancing is accomplished
>      by .... ? Placing the server in the list spares.tab?


>     How is the load at which the request is 'passed along' determined?

The least loaded server; lonnet.pm.
Determined essentially from /proc/loadavg (see lond).
cat /proc/loadavg; the fraction of processes that aren't getting
cpu time over the last minute, 5 minutes, 15 minutes, and then
I don't know the final two numbers.

# ------------------------------ Find server with least workload from

sub spareserver {
    my $tryserver;
    my $spareserver='';
    my $lowestserver=100;
    foreach $tryserver (keys %spareid) {
       my $answer=reply('load',$tryserver);
       if (($answer =~ /\d/) && ($answer<$lowestserver)) {
    return $spareserver;

>     How would I double my library server as an access server in a case of
>     emergencies (ie., really high loads).

treat it like one; place it in spare.tab; library servers have
access server functionality (plus "much much more")

>     I was seeing some peak loads in the >3 category for yesterday evening,
> and there are some complaints about system access. On the order of 20-26
> httpd children are kept alive most of the time.

congratulations? :) hmmm... maybe we need to look at how many httpd
are allowed to work at any one time.. don't know


>                                         Thanks,
>                                                  Mark
> ----------------------------------------------------------------------------
> Mark Lucas                                      email: lucasm@ohiou.edu
> 252D Clippinger Lab                             phone: (740)597-2984
> Department of Physics and Astronomy             fax:   (740)593-0433
> Ohio University
> Athens, OH 45701
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Scott Harrison -- Graduate Student
Microbiology and Molecular Genetics
Mich. State. Univ., East Lansing, MI
harris41@msu.edu, 517-353-0998