Filesystem buffer size

[Chuck Swiger]

Vivek Khera wrote:
> On Nov 8, 2004, at 4:20 PM, Charles Swiger wrote:
>> So long as the system has enough memory available for the working sets 
>> of the processes being run, FreeBSD will use the rest of the memory 
>> for caching stuff from the filesystem without needing any special tuning.
> 
> Are you sure of this?

No.  :-)  However, I'm willing to count not just the actual disk buffer cache 
itself, but process-level caching of files.  The OP didn't mention what kind 
of server application he was using, but things like squid and apache will 
buffer files into RAM (ie, the process' address space).

I am not as sure about things like NFS or Samba/CIFS.

> The disk buffer cache from what I have learned is 
> maxed out at 200Mb, which is a small fraction of a 4GB RAM box.

OK.  If you've got many hundreds of MBs worth to deal with, perhaps using 
md(4) would be a better idea.

-- 
-Chuck