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Path: euryale.cc.adfa.oz.au!newshost.anu.edu.au!harbinger.cc.monash.edu.au!news.rmit.EDU.AU!news.unimelb.EDU.AU!munnari.OZ.AU!news.ecn.uoknor.edu!news.wildstar.net!news.sdsmt.edu!nntp.uac.net!cancer.vividnet.com!hunter.premier.net!bofh.dot!news.mathworks.com!fu-berlin.de!zrz.TU-Berlin.DE!zib-berlin.de!irz401!uriah.heep!news From: j@uriah.heep.sax.de (J Wunsch) Newsgroups: comp.unix.bsd.freebsd.misc Subject: Re: FBSD-2.1-R: buffer cache configurable? Date: 21 May 1996 06:53:20 GMT Organization: Private BSD site, Dresden Lines: 24 Message-ID: <4nrp90$917@uriah.heep.sax.de> References: <4nqkn0$8n3@luva.lb.bawue.de> Reply-To: joerg_wunsch@uriah.heep.sax.de (Joerg Wunsch) NNTP-Posting-Host: localhost.heep.sax.de Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8bit X-Newsreader: knews 0.9.6 X-Phone: +49-351-2012 669 X-PGP-Fingerprint: DC 47 E6 E4 FF A6 E9 8F 93 21 E0 7D F9 12 D6 4E migieger@luva.lb.bawue.de (Michael Giegerich) wrote: > We would like to increase the buffer cache of our FBSD-2.1-R system > with 64 MB of RAM. > > With BSDI there are options like BUFMEM="N" that directly change > the size of disk buffer cache. Is there something alike in FBSD? FreeBSD >= 2.0.5 comes with the ``merged VM and buffer cache'', i.e. the size of the buffer cache is dynamically changed according to the needs. It does a really great job in this. If nothing else has an urgent need for the memory, you can even keep large files entirely in-core. This obviously makes iozone worthless with a file size < RAM size. I ran iozone yesterday to see how my optical disk performs, and i've accidentally specified 16 MB for the file size (on a 32 MB machine). The result was 80 seconds for writing, and some 0.7 seconds for reading the file. :) -- cheers, J"org joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE Never trust an operating system you don't have sources for. ;-)