Load average recommended thresholds (1083 Views)
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luissma
Posts: 26
Registered: ‎07-07-2008
Message 1 of 5 (1,083 Views)
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Load average recommended thresholds

Hi all,

I need to establish a policy for monitoring my HP-UX systems and I’m trying to figure out which would be the recommended thresholds for warning and critical load average alerts.

After having read a lot of documentation it’s not very clear for me what would be recommended values from top’s load averages.

Some people recommend maximum load averages of 3 or 4 and some other say there is a problem on the system only from values of 14-15 on.

I have, for example, a HP-UX 11.31 running on a ia64 hp server BL870c with following characteristics:

CPU info:
4 Intel(R) Itanium 2 9100 series processors (1.59 GHz, 18 MB)
532 MT/s bus, CPU version A1
16 logical processors (4 per socket)

Memory: 131041 MB (127.97 GB)


Top’s output usually shows values like following ones:

Load averages: 0.35, 0.39, 0.42
826 processes: 737 sleeping, 87 running, 2 zombies
Cpu states:
CPU LOAD USER NICE SYS IDLE BLOCK SWAIT INTR SSYS
0 0.46 29.7% 0.0% 6.9% 63.4% 0.0% 0.0% 0.0% 0.0%
1 0.25 41.6% 0.0% 8.9% 49.5% 0.0% 0.0% 0.0% 0.0%
2 0.47 23.8% 0.0% 5.0% 71.3% 0.0% 0.0% 0.0% 0.0%
3 0.26 47.5% 0.0% 6.9% 45.5% 0.0% 0.0% 0.0% 0.0%
4 0.50 25.7% 0.0% 9.9% 64.4% 0.0% 0.0% 0.0% 0.0%
5 0.24 21.8% 0.0% 3.0% 75.2% 0.0% 0.0% 0.0% 0.0%
6 0.42 15.8% 0.0% 7.9% 76.2% 0.0% 0.0% 0.0% 0.0%
7 0.26 15.0% 0.0% 6.0% 79.0% 0.0% 0.0% 0.0% 0.0%
8 0.44 29.0% 0.0% 6.0% 65.0% 0.0% 0.0% 0.0% 0.0%
9 0.27 23.0% 0.0% 2.0% 75.0% 0.0% 0.0% 0.0% 0.0%
10 0.42 74.0% 0.0% 2.0% 24.0% 0.0% 0.0% 0.0% 0.0%
11 0.25 21.0% 0.0% 3.0% 76.0% 0.0% 0.0% 0.0% 0.0%
12 0.40 20.0% 0.0% 7.0% 73.0% 0.0% 0.0% 0.0% 0.0%
13 0.26 17.0% 0.0% 5.0% 78.0% 0.0% 0.0% 0.0% 0.0%
14 0.42 97.0% 0.0% 0.0% 3.0% 0.0% 0.0% 0.0% 0.0%
15 0.26 5.0% 0.0% 1.0% 94.0% 0.0% 0.0% 0.0% 0.0%
--- ---- ----- ----- ----- ----- ----- ----- ----- -----
avg 0.35 31.7% 0.0% 5.0% 63.4% 0.0% 0.0% 0.0% 0.0%


I’d thank if somebody could put some light on all this and let me know when could I run into trouble with load average. Of course, I should consider some other facts like slowness of system, etc, etc, but for the moment I need to take a specific value to set my alerts.

Thanks in advance.
Honored Contributor
Hakki Aydin Ucar
Posts: 1,314
Registered: ‎08-16-2006
Message 2 of 5 (1,083 Views)

Re: Load average recommended thresholds

Your current status ,load average is good (very low)

If you use (if you have) glance tool ,you can use its default, to analyze load average.
By default cpu bottleneck is around 50% ,alarm will be triggered as warning in glance.

additionaly, On multi-processor systems, the values represent the average over all CPUs.
Thus the percentage columns never exceed 100. For individual processor detail,
use the 'a' (CPU By Processor) screen.
Honored Contributor
Honored Contributor
TTr
Posts: 3,434
Registered: ‎01-22-2008
Message 3 of 5 (1,083 Views)

Re: Load average recommended thresholds

The CPU load is a very misleading metric including its name.

You can have a load below 1 and have a serious bottleneck and vice-versa you can have a load of 20 and have a very responsive system.

Look at Bill's responses in these threads

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=750840

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=876751

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=452648

http://forums11.itrc.hp.com/service/forums/questionanswer.do?threadId=1071636
I do not reply to forumers who 1) consistently don't assign points, 2) ask for step-by-step instructions for a topic but appear to have no IT experience and make no effort to learn. Some exceptions for newcomers and special topics.
Honored Contributor
Court Campbell
Posts: 1,605
Registered: ‎08-12-2004
Message 4 of 5 (1,083 Views)

Re: Load average recommended thresholds

I have always hated the load average output. It may be because I have known old school admins that place to much emphasis on it. From my understanding you are possibly hitting a bottleneck if your load average is nearing the same amount you have in cpus/cores. So if your load average starts getting close to 16, then you might have a problem. I say might because it is not necessarily bad that your processors are doing work. Tuning is a science and an art. You really how the system is supposed to function and what your users are expecting. I would suggest getting some baseline data and making comparisons along the way.

It is hard to give an exact number since every server/application is a little different. There are no hard set numbers to give anyone. That is why performance/tuning guys make lots o' cash. In the words of any good tuning guru, the answer is "It depends".
"The difference between me and you? I will read the man page." and "Respect the hat." and "You could just do a search on ITRC, you don't need to start a thread on a topic that's been answered 100 times already." Oh, and "What. no points???"
Advisor
luissma
Posts: 26
Registered: ‎07-07-2008
Message 5 of 5 (1,083 Views)

Re: Load average recommended thresholds

Understood. Thanks to all, including Bill Hassell :)

Regards,

Luisma Arranz
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