Re: mod_cache performance

[Brian Akins]

Eli Marmor wrote:
Graham Leggett wrote:
 

Brian Akins wrote:
   

On an OS that supports sendfile, a disk based cache will almost always
bury a memory based one.
     

Quite probably. But on a system without a disk, chances are it won't. :(
   

It will.
Unless mod_disk_cache + ram-disk + sendfile doesn't outperform
mod_mem_cache.
 

This setup performs quite nicely on Linux.
The big hits for mem cache are:
The cache is not shared between processes, so you use alot more memory 
and have a lot less "hits."

You have to copy data from user to kernel, which can be a huge hit.
Even without sendfile, mmap is generally faster than mem cache.
--
Brian Akins
Senior Systems Engineer
CNN Internet Technologies