Advice on CPU Loads


It isn’t an issue at the moment, but we are anticipating a large increase in websites over the next year, which will in turn have a knock-on effect on CPU load. At the moment its running 0.24 (1 mins) , 0.28 (5 mins) , 0.31 ( 14 mins), but I can see the 15 mins process heading towards 1.0 in coming months.

I was wondering what people think in terms of CPU loads, and specifically what levels you would consider CPU to be running too high and feel action is needed. Or would you use a different measure than this?

Any thoughts welcome. Many thanks in advance.

I’ve seem hosts/server admins argue that a load of 1 for each CPU on the machine is acceptable. Now, most hosts that want performance out of their servers will prefer that the level I mentioned is only reached during traffic peaks, and the long term average be significantly lower.

I’m talking about dedicated servers. If you have a VPS, this complicates the estimates. You’re better off guiding yourself by the websites’ performance during the peaks.

At the end of the day, server load (it is not CPU load/usage), is just a synthetic metric. A server can in theory have a load of 300 and run just fine. :slight_smile:

Thanks for your reply ldcdc.

We run dedicated servers, and up till now I haven’t had much involvement in their management, mering programming sites.

So the CPU load can give you some idea, but doesn’t always tell the whole story? Maybe benchmarking the sites, tallying their performance and making any speed improvements? I guess at the end of the day its about making the servers (and websites) as efficient as possible.


You should try to optimize web server and mysql server. In many cases I have seen that this trick has played an important role. But, first thing is that to know the cause of Cpu load.


Thanks for the replies guys, very helpful.

One of the other servers we run, although I’m not as actively involved with, is actually running with CPU loads of around 3 and above, even at 15 minutes. The culprit for this however is an email sender, which is using about 70% of the CPU. This has gotta be too much hasn’t it - overloading server by more than 300%? Viewing the email sender control panel is noticeably slower.

I’ve increase cron job time increments, plus removed any page compression scripts, which use up CPU. This should help in short term, but bigger changes will be needed.