Linux Server Load in Perl ?

Does anyone know of a GPL script or how I would go about creating a script that checks the current server load on a Linux/Apache webserver

Basically I am trying to modify a GPL Perl backup script like this pseudo-code

if ( ServerLoad < 15% ) {

DoSomething();

}
else
{

DoNothing();

}

It all really depends on what you mean by load. If you're referring to load average, you can simply parse the output of uptime and use the value that's the most important to you.

For example:

Code:

---

$uptime = `uptime`;
$uptime =~ /load average:(.*)$/;
@avg = split /\,/,$uptime;
foreach (@avg)
{
  print "Load: $_\n";
}

---

I'm sure there are also perl modules that will give you different metrics...

OK what I mean by "load" is that I want to determine if the current CPU usuage is above a given percentage ? Does that make sense ?

Then parse the output of vmstat. It will give you the percentage of CPU used for user requests, system requests, and idle %. I'd subtract the idle stat from 100 and you'll have the total % utilization.

Code:

---

@output = `vmstat`;
$idle = (split ' ', $output[-1])[14] # Get the last line of the vmstat output, get the idle column
print "Idle: $idle%\n";
print "Total Utilization: " . (100 - $idle) . "%\n";

---

I'd run vmstat a few times and get the average depending on what you're trying to do...

Again, there is likely a perl module that does this for you...

If there is a perl module that does this already, how would you suggest that I go about finding out which one that it is ?

thanks for the help

Check on CPAN / etc. Or you can use the above script.

Thanks - I decided to go ahead and use the script you provided.

I had to change a little to account for the fact that on my architecture the idle time is not in column 16.

Here's what I ended up with

Code:

---

@output = `vmstat`;
@cols = (split ' ', $output[1]);
$colcount = 0;
$col = 0;

foreach(@cols) {
 if ($_ == "id" ) {
  $col = $colcount;
 }
 $colcount++;
}

$idle = (split ' ', $output[-1])[$col];
$load = 100 - $idle;

---

works like a charm!

Thanks so much for the help