What does the server load mean ??

Hi all,

As the title says what does the server load mean ??

Were currently monitoring one of our servers and I have the following on the screen now:

Load:
99.5% ( 3.98, 3.57, 2.84 )

Memory Used:
41.3%

Swap Used:
7.1%

I’m a little confused as the Load is reporting 99.5% however the sites are still loading as fast as ever, also what are the 3 things after it in the brackets ( 3.98, 3.57, 2.84 )

Just learning this server stuff so go easy on me

Thanks

Hey paulp,

The server load numbers are 1, 5, and 15 min so you can see if load is increasing or decreasing. Generally you shouldn’t worry until you hit around 6 or higher, granted if you can reduce the load that never hurts.

The other thing to watch is swap usage, if you start using a lot of swap things will come to a crawl as disk space is being used instead of memory.

Hope that helps some
AMDbuilder

Thanks AMDbuilder,

Does that mean I can ignore the % on the load as long as the other 3 to the right or it are under 6 ??

Cheers

You can’t ignore such % of load, it can be some tuning problems, DDOS attacks signs or maybe just a weak server hardware.

Typically I don’t worry about the load %, but instead focus on the 1 min (first number) load value. Ideally the load should be under the number of processors, so if you have 2 processors a load under 2. A load level of say 2-4 in that example would be high and you should look for a cause, 4-6 you should be trying to reduce the load, over 6 and the server may have issues.

If you can tell me more about the server I can give you better suggestions regarding the load, or ask your hosting company what they suggest.

Thanks AMDbuilder,

Server specs are as follows:

CPU: Quad-Core AMD Opteron(tm) Processor 1354
Number Of CPU(s): 4
Avg Load: 0.89, 0.87, 0.96
Memory: 2 GB / 8 GB
Swap: 2GB
Speed: 1100.000MHz
HDD: 500GB
Free HD space: 372GB
PHP Version: 5.2.14
MYSQL Version: 5.0.91-community
Webserver Version: 2.2.16
Linux Distro: Red Hat Enterprise Linux Server release 5.3 (Tikanga)
Kernel: 2.6.18-194.17.1.el5
Platform: x86_64

The server load reported above was due to Rackspace doing their backups, I’ve stopped that from happening at peak times now and it done at 3am GMT going forward. Current load on the server is 43.3% ( 1.89, 1.49, 1.18 )

And pointers you could give would be great.

Thanks

Any advice you can give would be great

Hello paulp,

You are going to want load to be 4 or less with that server, if you go over 4 things will start running slowly. You’ve got plenty of memory so you could use that on higher traffic sites to cut down on load (serving from memory vs processing via php). If you’re load is normally at or under 1 you should be fine.

If you have pingdom watch the server responsiveness it should help you figure out periods where the server may be running slower than normal, look through the logs at that point in time to narrow things down.

You can read more on all this here: http://aplawrence.com/Unixart/understanding_load.html

Thanks AMDbuilder,

That’s been a great help