Interpreting 'top' or 'ps' Memory info

[thedaver]

When I run 'top' or 'ps' to see the memory output of the various processes, I see the 'size', 'rss', and 'share' stats. Normally 'size' and 'rss' are the same value, and 'share' is less. My reading of the 'top' manpage indicates that the shared space appears to be shared from what is most likely shared library routines??

Blah Blah, here's why I'm asking...

On a 512MB RAM box, I'm trying to figure out a hard limit for my Apache 'httpd' max servers value. I'm thinking I'll allocate 300MB to that server and its children, but I can't figure out how many 'httpd' children that allocation might allow since I can't understand whether the 8MB size/RSS is the per-child "cost" or if the 8MB-6MB(shared)=2MB is the per-child "cost"

Q: How do I figure out the incremental memory "cost" of each new "httpd" process.

Thanks.
D.

 

[Morsing]

Each child doesn't take up 8MB because it uses the same text and data segment as the parent. I don't even think it will use 2MB probably more like a few hundred kbs.

300Mb will give you a lot of httpd processes.

What is the requirements of the box?? How many connections do you expect??

Cheers

Henrik Morsing
Certified AIX 4.3 Systems Administration
& p690 Technical Support