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Path: euryale.cc.adfa.oz.au!newshost.carno.net.au!harbinger.cc.monash.edu.au!news.mira.net.au!news.netspace.net.au!news.mel.connect.com.au!news.syd.connect.com.au!news.bri.connect.com.au!fjholden.OntheNet.com.au!not-for-mail From: Tony Griffiths <tonyg@OntheNet.com.au> Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: Question re: Unix setting aside 10% of RAM for disk cache Date: Mon, 14 Apr 1997 08:46:13 +1000 Organization: On the Net (ISP on the Gold Coast, Australia) Lines: 47 Message-ID: <33516235.DAA@OntheNet.com.au> References: <5ipqh4$flt@news.leonardo.net> Reply-To: tonyg@OntheNet.com.au NNTP-Posting-Host: swanee.nt.com.au Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Mailer: Mozilla 3.0 (WinNT; I) To: driess <driess@movieweb.com> Xref: euryale.cc.adfa.oz.au comp.unix.bsd.freebsd.misc:39019 driess wrote: > > I am running BSD2.0 & when I bootup the machine, Unix automatically > takes 10% of my available RAM (in my case 96megs of total RAM) & uses > this 10% for the disk-cache (9.6 megs are used for our disk-cache) ... Ultrix (the DEC implementation of Unix based on BSD4.2) also did this! The version of FreeBSD you are running is WAY WAY WAY out of date... Upgrade to at least 2.1.7.1 or maybe 2.2.1 asap!!! > > Is this standard in Unix that the system allocates 10% of total RAM > for the disk-cache and if so, what file do I need to modify so that I > can alter this setting? For the release you have, yes. Can you alter it, probably. Mining my grey matter and associated protein store, I seem to recall a keyword that you could put in the kernel build file to change the %age of memory allocated (DEDICATED, it can't be used for anything else!) to the buffer cache. Eg. <stuff> bufcache 25 #20% of RAM goes to buffer cache <other-stuff> Now config your modified kernel definition file and recompile/relink it and you should be away. > > When I run TOP, it tells me that the server never has less than 55megs > of available (Free) RAM ... so I'm thinking of using this unused > memory to increase the disk cache. > > ANY SUGGESTION? Thanks Apart from the above, I would strongly suggest going to at least 2.1.7.1 or later. All of the 2.1.x releases had an "integrated" bufcache/free-memory pool and 'dynamically' balanced memory usage. If no programs wanted memory, it was available to the buffer cache but when they did want it, pages were reclaimed from the cache. This is a MUCH better way of doing things!!! > Dave Riess > driess@movieweb.com Tony