Subject: Re: bufpages
To: Tom T. Thai <email@example.com>
From: Greg Wohletz <greg@duke.CS.UNLV.EDU>
Date: 06/24/1998 17:09:13
>On Tue, 2 Jun 1998, Jukka Marin wrote:
>> I want to improve performance of a largish news server which has 80 MB
>> of RAM. According to options(4), I have to set options NBUF and/or
>> BUFPAGES. However, there is no information of the range of these
>> constants - not even in the sample kerne config files.
> I'm building a NetBSD 1.3.2 kernel. How should I set these constants?
>maxusers 200 # estimated number of users
>options BUFPAGES=4096 # 16MB for disk buffering
What are the limitations for these paramters? On one of our fileservers
that has 32meg of ram, if I set BUFPGES/NBUF > 1024 it panics during
autoconfig (pmap_pte returns null causing a ``ptdi'' panic in
arch/i386/i386/pmap.c). Is there a maximum ratio of BUFPAGES to real mem?
Also, are any statistics kept by the kernel that I can query on the
effectiveness of the disk buffer cache?