Disk buffer / memory utilization

[Eric Anderson]

R. Payette wrote:
> I'm trying to get the best performances from a ratter limited system. My 
> question is 2 fold :
> 
> 1- the 'buf' column in top, I thought freebsd ( and other modern OSes ) 
> used free memory for disk buffer until it is required for something 
> else. But I see on my system that the 'buf' is always 14 M no matter the 
> load on the server, even in heavy swapping situations, it remains 14 M.
> 
> 2- how to reduce the wired memory ? I have a lean custom built kernel 
> and 17M ( around 22M after a few hour of utilization ) is a little to 
> much to be normal. I mean, out of the 64M this machine has, 36M are 
> locked out by the bare system which has, a network card, a hard disk and 
> an unused video card ( headless machine ).
> 
> Is there something I can tune in sysctl or my kernel conf ? or is it a 
> concept I don't get correctly ?

I would strongly suggest reading the 'tuning' man page - it's really 
pretty good, and should answer some of your questions (maybe not 
specifically, but indirectly about tuning some sysctl's and such).

Which such a small amount of memory, you're going to have to work harder 
at getting it just right.

You should also mention what you are trying to make perform well on this 
system, what version of FreeBSD, and maybe also the hardware information.

Eric



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Eric Anderson     Sr. Systems Administrator    Centaur Technology
Talk sense to a fool and he calls you foolish.
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