My web host only provides 64-bit OS, but the 64-bit Apache webservers take too much memory and occasionally lead to thrashing, under not too much external load.
Is there any way to configure Apache to use less memory, or do you suggest any other configuration?
My server has 256MB RAM and runs one wordpress and two other subdomains with static pages.
Current Apache process configs as shown by Webmin are:-
Min processes: 10
Max processes: 15
Initial startup processes count: 8
Max simultaneous connections per process: 4000
Update:- Right now I see 11 Apache processes running each taking about 360MB of RAM on my 256MB system!
If you really think it'll make a difference, just install a 32-bit Apache binary and modules and run that instead. That's the only way to "make 64-bit Apache behave as 32-bit". It's not simple, and a maintenance nightmare, though -- I wouldn't recommend it.
There are a pile of ways to make Apache use less memory, but you're making incremental gains there, and if you've got only 256MB of RAM to play with, you're going to need a big change -- and nginx is the one I'd recommend. It doesn't spawn dozens of workers, and each of the 2-4 it does use only take a few MB each (the one in front of me at the moment, running about a dozen vhosts, is taking up 2448kB resident).
This has nothing to 32bit vs. 64bit.
Why do you think 15 Processes at 60MB each (just a guess) will use less than 900MB of memory when running on a 32bit architecture?
I'd rather run some numbers.