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</o:shapelayout></xml><![endif]--></head><body lang=EN-US link=blue vlink=purple><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal style='margin-left:.5in'><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> nap [mailto:naparuba@gmail.com] <br><b>Sent:</b> Tuesday, April 02, 2013 2:48 AM<br><b>To:</b> Nagios Users List<br><b>Subject:</b> Re: [Nagios-users] Help with CPU Check Thresholds<o:p></o:p></span></p><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><div><div><p class=MsoNormal style='margin-left:.5in'>On Mon, Apr 1, 2013 at 2:05 PM, Scott Wilkerson <<a href="mailto:swilkerson@nagios.com" target="_blank">swilkerson@nagios.com</a>> wrote:<o:p></o:p></p><p class=MsoNormal style='margin-left:.5in'>Alex,<br><br>It would be very common for a machine with multiple CPU's to have a<br>higher load. On a 16 CPU machine, no processes would be waiting at all<br>with a load under 16.<o:p></o:p></p><div><p class=MsoNormal style='margin-left:.5in'><o:p> </o:p></p><div><div><p class=MsoNormal style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:.5in'>Hi,<o:p></o:p></p></div><p class=MsoNormal style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:.5in'>Yes if all the load is consumed by CPUs, but it's quite rare. For example with a database the most time is spend on disks I/O, and a 16cpu server won't help here, you can be overload with a load average > 1 in this case.<o:p></o:p></p></div><p class=MsoNormal style='margin-left:.5in'>The "good" load average is very specific for each server/application. CPU number is a just a part of the "load" equation.<o:p></o:p></p><div><p class=MsoNormal style='mso-margin-top-alt:0in;margin-right:0in;margin-bottom:12.0pt;margin-left:.5in'><o:p> </o:p></p></div><p class=MsoNormal style='margin-left:.5in'>Jea<span style='color:#1F497D'>n</span><o:p></o:p></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I think that’s rather a misunderstanding of what load average is. It is not based on the CPU (otherwise it would be called something stupid like CPU % on Windows). There’s lots of resources on the Googles that explain what goes into the load average calculation so I won’t go into it here, but it is intended to be a general number indicating the load of the system and i/o wait times are definitely a factor in that calculation. It is intended to be a representation of how busy a machine is overall. The general rule is as Scott indicates that for a machine with ‘n’ CPUs (cores, kind of as well) if the load average is also ‘n’ then that machine is 100% utilized. That is, it is completely able to keep up with what it’s being asked to do. If the load average is ‘2n’ then it’s 200% utilized and the machine is effectively getting behind.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>But anyway, there are some really good write-ups as to how the load average calculation is made, but it’s definitely not just CPU. CPU utilization by itself is pretty useless nowadays in my opinion.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Mark<o:p></o:p></span></p></div></div></div></div></div></body></html>