From owner-freebsd-questions@FreeBSD.ORG Wed Sep 2 03:16:35 2009 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 28258106566C for ; Wed, 2 Sep 2009 03:16:35 +0000 (UTC) (envelope-from dan@dan.emsphone.com) Received: from email2.allantgroup.com (email2.emsphone.com [199.67.51.116]) by mx1.freebsd.org (Postfix) with ESMTP id E0AA88FC0A for ; Wed, 2 Sep 2009 03:16:34 +0000 (UTC) Received: from dan.emsphone.com (dan.emsphone.com [199.67.51.101]) by email2.allantgroup.com (8.14.0/8.14.0) with ESMTP id n823GUaO055947 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 1 Sep 2009 22:16:31 -0500 (CDT) (envelope-from dan@dan.emsphone.com) Received: from dan.emsphone.com (smmsp@localhost [127.0.0.1]) by dan.emsphone.com (8.14.3/8.14.3) with ESMTP id n823GUC0050455 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO) for ; Tue, 1 Sep 2009 22:16:30 -0500 (CDT) (envelope-from dan@dan.emsphone.com) Received: (from dan@localhost) by dan.emsphone.com (8.14.3/8.14.3/Submit) id n823GUS9050453; Tue, 1 Sep 2009 22:16:30 -0500 (CDT) (envelope-from dan) Date: Tue, 1 Sep 2009 22:16:30 -0500 From: Dan Nelson To: Per olof Ljungmark Message-ID: <20090902031626.GD2855@dan.emsphone.com> References: <4A9D8057.8020307@intersonic.se> <20090901162931.d85ec256.wmoran@potentialtech.com> <20090901204147.GC2855@dan.emsphone.com> <4A9DB3AE.1000400@intersonic.se> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4A9DB3AE.1000400@intersonic.se> X-OS: FreeBSD 7.2-STABLE User-Agent: Mutt/1.5.19 (2009-01-05) X-Virus-Scanned: ClamAV version 0.94.2, clamav-milter version 0.94.2 on email2.allantgroup.com X-Virus-Status: Clean X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-2.0.2 (email2.allantgroup.com [199.67.51.78]); Tue, 01 Sep 2009 22:16:33 -0500 (CDT) X-Scanned-By: MIMEDefang 2.45 Cc: freebsd-questions@freebsd.org Subject: Re: memory usage displsy X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Sep 2009 03:16:35 -0000 In the last episode (Sep 02), Per olof Ljungmark said: > Dan Nelson wrote: > > In the last episode (Sep 01), Bill Moran said: > >> In response to Per olof Ljungmark : > >>> What is a good way to find out how memory is used? Have a 6.4 box > >>> where memory is used by something but I fail to see what is using it - > >>> tried different switches to ps(1), tried the stat tools but a big > >>> chunk of memory does not show at all. > >>> > >>> A proper tool for analyzing memory usage "live", this is a production > >>> box? > >> > >> I've always been able to get what I need from top. You can do -o res to > >> sort by resident memory usage, which helps. > > > > ps will sort by memory usage when given the -m flag. Also check ipcs -a > > to see if there are any sysv shared memory segments hanging arnound. If > > you don't see anything using the memory, where are you seeing that > > "something" is using it? > > What I see is a slapd process using about 150M, then around a hundred imap > processes 5-10M each. If the server is restarted, 70-80% will be free, > now, after three months we're at 11% free loosing about 20% per month. > > The exact sum VSZ right now as shown by ps is 1073632k but top says > > Mem: 3111M Active, 311M Inact, 230M Wired, 144M Cache, 112M Buf, 27M Free > > Clearly something is grabbing memory and not releasing it. Disk cache, most likely. I would expect "Free" memory as reported by top to drop down to under 100MB a few hours after a system is rebooted. The difference between Active->Inact->Cache->Buf is more an indication of how long ago a particular page has been touched (and how much work it is to map the page back into a processes memory space), and doesn't really say what the block is being used for. If you are not actively swapping, there is no need for panic. Even a couple hundred MB of used swap is fine, as long as you're not constantly having to pull it back into memory. http://www.freebsd.org/doc/en/books/arch-handbook/vm.html has a good rundown of how the VM system works. -- Dan Nelson dnelson@allantgroup.com