Re: Performance difference between 2 machines

Matthias Hoys wrote:
> Mmm ... this is getting more complicated than I thought ;-) Yes we are using
> async i/o, but no direct i/o (although the filesystem buffer cache has been
> set pretty low, so this might have the same effect as activating direct i/o
> ?).
>

The big difference: usually direct i/o will bypass most VM mechanisms while even a non aggressive caching won't.

> Now what about RHLES 3.0 on VMWare 5.0 on Windows 2000 ? ;-)
>
>

This is really complicated!

RHLES 3.0 would buffer by default and would use aio. But the harsware is vitualized by you vmware gsx... and there I'm lost... At the end windows is going to perform the real i/o calls and it go with direct i/o by default (even on filesystem).

I surrend this answer to a good VMWARE adept!

-- 
Fabrizio Magni

fabrizio.magni_at_mycontinent.com

replace mycontinent with europe