"Processes and Limits" simple questions

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#1 Tue, 04/19/2011 - 09:43
wattaman

"Processes and Limits" simple questions

Under Virtualmin>domain-name.com>Services>Configure Website>Processes and Limits, if I want to limit the domain-name.com's access to CPU or memory, what I should write for the CPU and for the memory? (is it percentage, MB,GB etc?) Also: - what is the Soft/Hard limit? - "Maximum request body size" is the size of (any) web page? - what is the "Process limit"? ...sorry, couldn't find it in the documentation area.

Tue, 04/19/2011 - 09:53
andreychek

I believe that area configures the PAM limits (in /etc/security/limits.conf).

Knowing that -- you can see what all the various settings do by looking at "man limits.conf" from the Linux command line.

-Eric

Wed, 04/20/2011 - 10:43
wattaman

Andrey, I'm not smart enough for the command line. That's why I use Virtualmin, is easier for me :) Can you give an advice, please, regarding how to set the limits on through the page I've mentioned above? Thank you!

Wed, 04/20/2011 - 11:01
andreychek

Well, those limits are rather complex... I don't recommend attempting to tweak those without understanding exactly what they do :-)

If there was a good all-around number for how to set those, it would be set that way by default... unfortunately, there isn't -- it completely depends on your specific needs -- what sort of resources the users require, what resources the applications they use require, and what your server is capable of.

So, you need someone to review your server and your requirements, evaluate the various components involved, and to put in some numbers. And even after all that -- you'd need to do a rather thorough review to make sure they're correct :-)

Those limits are harsh -- if they don't correctly take your needs into account, they'll cause the applications to fail, and users accessing the site would receive "500 Internal Server" errors.

If you still really want to use those, I might suggest ignoring the CPU and RAM limits, and to add only process limits -- those specify how many processes a give user is allowed to create. Setting that would prevent too many processes from spawning, while allowing applications to use whatever CPU and RAM they require.

But again, there's no specific number I can give you to set it to, it depends on a lot of factors... figuring that out would be a matter of trial and error :-)

-Eric

Wed, 04/20/2011 - 22:24
wattaman

I could try to tweak anything, there's no problem if the server will not function properly for a few days , but you still haven't answered me what should I type there :) I was not asking for the exact values, as those depend, of course, of what the server is doing and its specifications. I just wanted to know if, on that page, should I enter only numeric values (NOT 64MB, for example, JUST 64 ... right?!) and also if those numbers/fields are referring to percentage or MB, GB etc., for the cpu and the memory. Cheers!

Wed, 04/20/2011 - 23:46
andreychek

Here's a link to a website containing the manpage for the PAM limits that the "processes and limits" screen uses:

http://linux.die.net/man/5/limits.conf

Look at "nofile", "cpu", and "rss" for details on open file, cpu, and memory limits.

It also describes the difference between soft and hard limits.

-Eric

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