From owner-freebsd-performance@FreeBSD.ORG Tue Mar 19 11:00:08 2013 Return-Path: Delivered-To: freebsd-performance@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id 44A047B3 for ; Tue, 19 Mar 2013 11:00:08 +0000 (UTC) (envelope-from rkearsley@blueyonder.co.uk) Received: from mtaout02-winn.ispmail.ntl.com (mtaout02-winn.ispmail.ntl.com [81.103.221.48]) by mx1.freebsd.org (Postfix) with ESMTP id 983E5997 for ; Tue, 19 Mar 2013 11:00:07 +0000 (UTC) Received: from know-smtpout-1.server.virginmedia.net ([62.254.123.3]) by mtaout02-winn.ispmail.ntl.com (InterMail vM.7.08.04.00 201-2186-134-20080326) with ESMTP id <20130319110000.HBXI23282.mtaout02-winn.ispmail.ntl.com@know-smtpout-1.server.virginmedia.net>; Tue, 19 Mar 2013 11:00:00 +0000 Received: from [87.194.108.92] (helo=[192.168.1.168]) by know-smtpout-1.server.virginmedia.net with esmtpa (Exim 4.63) (envelope-from ) id 1UHuEN-0000tl-Er; Tue, 19 Mar 2013 10:57:23 +0000 Message-ID: <51484494.5090604@blueyonder.co.uk> Date: Tue, 19 Mar 2013 10:57:24 +0000 From: Richard Kearsley User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130106 Thunderbird/17.0.2 MIME-Version: 1.0 To: freebsd-performance@freebsd.org Subject: buffer cache usage Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Cloudmark-Analysis: v=1.1 cv=GaEGOwq9FwezmTggA+b6yC6zDZF2HYaK6RN/tSqdnVA= c=1 sm=0 a=D6wcrpBcUpcA:10 a=3NElcqgl2aoA:10 a=8nJEP1OIZ-IA:10 a=9rJ3xXJf5Y35wX6ri6YA:9 a=wPNLvfGTeEIA:10 a=HpAAvcLHHh0Zw7uRqdWCyQ==:117 X-BeenThere: freebsd-performance@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: Performance/tuning List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 19 Mar 2013 11:00:08 -0000 Hi I'm using FreeBSD and nginx as a web server serving static files. I always like the "buffer cache" which lets frequently used files stay in memory rather than read from disk again. I have a new server with 32GB of ram and I notice a lot of memory is listed as "Inact": Mem: 688M Active, 26G Inact, 3758M Wired, 823M Cache, 3281M Buf, 173M Free What's preventing this ram from being used as buffer cache for files on the hard disks? Is there a limit or a tunable stopping it? I never had a server with this amount of ram before. It's a very busy server, I'm sure a lot of files are accessed regularly as the disks are always busy. Using 9.1 amd64: FreeBSD richard 9.1-RELEASE FreeBSD 9.1-RELEASE #0 r243825: Tue Dec 4 09:23:10 UTC 2012 root@farrell.cse.buffalo.edu:/usr/obj/usr/src/sys/GENERIC amd64 Many thanks