From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from lists.gentoo.org (pigeon.gentoo.org [208.92.234.80]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by finch.gentoo.org (Postfix) with ESMTPS id 59094138330 for ; Mon, 10 Oct 2016 06:45:33 +0000 (UTC) Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 3F7DCE094C; Mon, 10 Oct 2016 06:45:26 +0000 (UTC) Received: from mail-lf0-f41.google.com (mail-lf0-f41.google.com [209.85.215.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pigeon.gentoo.org (Postfix) with ESMTPS id B9E2FE08E1 for ; Mon, 10 Oct 2016 06:45:25 +0000 (UTC) Received: by mail-lf0-f41.google.com with SMTP id b81so109560284lfe.1 for ; Sun, 09 Oct 2016 23:45:25 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=date:from:to:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=Qcd3KrJHJCXwf/piPBxXUmA4f/r8q5IrQZMBvyiaH6s=; b=OE7MA1EF357Q6TyrpegqAczzVRLSmSN0ARD4+5v/Bff1DZfvavR/6Sk92SFLI5Jhbm YVYL3l/s1x9yzgO6y1NYjpdvlFvom7Mu43F/0BdoXsuHp4OJFOpMZTwX+dpahBEMB0Z4 9CMj0aQJK+DIQuJdx85KLs22TQnf8VEAaN8qiWPT2iFM6qnoJBI6nvljdM/kgpsps64y loj1/AFwnHlLxiupV56rW4LQ9+NwKR3fJsF7DfEzhpbzs+6WqdMSODzrrPROFDpqmNAu qZvv9SyjbJwg0o7OX/QnvrO94oEtgRrTFeUmTqxDgIItwkXr5dA6LXUTWHfJ0QnC1eJy SGow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:date:from:to:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=Qcd3KrJHJCXwf/piPBxXUmA4f/r8q5IrQZMBvyiaH6s=; b=fsHe6kb3euKcCg69o0KnpeSWJ85uMnQomUf6HN9tu1C/3zob3tbEMTB5rjPcpe42Or mzo3Cac1iF57KDnNm4MJqjAKWbjinMv4CswC1iZpt/JsUShaHZ+JQs1AUjQOonQBGng2 SVlP0nNNMgw1I8AjdF3rOP3FluWv2XqLPYRN1Ye/V1d6wCW3NtkZlasgqGZDOaBoXB92 jYqE9hQfyPrsDsBsw8ewcCR6OWrolHEEkmIOFi06jU4enbF+f0c2CbrQKE9kLGawQ2oC Xf997M8oCCVSo5ynUneUXbLR2EDunZAmM0rpM2XFAasmgN/RS6KZPZnKxI8Fvbkfo1IM vvyg== X-Gm-Message-State: AA6/9Rm80/2CltCuswolHCX7ZgZAwFFT6OnBKhqdXDXRzQXKMwfadYwcOu/Vnu5MREj5eQ== X-Received: by 10.194.134.102 with SMTP id pj6mr28336912wjb.187.1476081923797; Sun, 09 Oct 2016 23:45:23 -0700 (PDT) Received: from gentoo-tp (fedora-jepio.cern.ch. [188.184.129.132]) by smtp.gmail.com with ESMTPSA id rk14sm37431952wjb.6.2016.10.09.23.45.22 for (version=TLS1_2 cipher=AES128-GCM-SHA256 bits=128/128); Sun, 09 Oct 2016 23:45:22 -0700 (PDT) Date: Mon, 10 Oct 2016 08:45:28 +0200 From: Jeremi Piotrowski To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] Strive for zero swap usage? Message-ID: <20161010064528.GA10878@gentoo-tp> References: Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.24 (2015-08-30) X-Archives-Salt: 68a97bba-e75d-4103-81f8-4be3c7c9c2b2 X-Archives-Hash: 85ee0655afe92da13543c25d556a3729 On Thu, Oct 06, 2016 at 03:31:59PM -0700, Grant wrote: > > Does this look OK? It looks to me like heavy swapping in and out with > plenty of free memory (minus buffers/cache). > Have you looked at the _units_ displayed by vmstat and munin? You're looking at **kilobytes** being swapped and calling that _heavy swapping_... In general your system shows that you have a lot of memory used as cache, and I would guess that the kernel thinks its better to keep using that memory for caching and swap out the occasional page of application data. The alternative would be dropping some cache - might be worse for performance. Swapping does not seem to be something that could be causing any issues for you. Do you even have an issue with response times of your webservers? If so (which you haven't explicitly stated here) it would be better for you to look at things from that end - what is taking long in the webserver and what is causing those things to take that long. As it stands, you're using anti-methods of performance analysis: Streetlight Anti-Method: 1. Pick observability tools there are familiar 2. Run tools 3. Look for obvious issues and Traffic Light Anti-Method 1. Open dashboard (munin) 2. All green? Assume everything is good 3. Something red? Assume that's a problem If you're really interested in this kind of stuff I recommend checking out the materials that Brendan Gregg has gathered over the years. http://www.brendangregg.com/methodology.html and other links on his page.