From owner-freebsd-current@freebsd.org Sat Aug 19 19:50:30 2017 Return-Path: Delivered-To: freebsd-current@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 8ABC6DE038A for ; Sat, 19 Aug 2017 19:50:30 +0000 (UTC) (envelope-from cy.schubert@komquats.com) Received: from smtp-out-no.shaw.ca (smtp-out-no.shaw.ca [64.59.134.9]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client CN "Client", Issuer "CA" (not verified)) by mx1.freebsd.org (Postfix) with ESMTPS id 54ED92E65; Sat, 19 Aug 2017 19:50:29 +0000 (UTC) (envelope-from cy.schubert@komquats.com) Received: from spqr.komquats.com ([96.50.22.10]) by shaw.ca with SMTP id j9lKd9GV7I8mCj9lMd5e2Q; Sat, 19 Aug 2017 13:50:28 -0600 X-Authority-Analysis: v=2.2 cv=HahkdmM8 c=1 sm=1 tr=0 a=jvE2nwUzI0ECrNeyr98KWA==:117 a=jvE2nwUzI0ECrNeyr98KWA==:17 a=kj9zAlcOel0A:10 a=KeKAF7QvOSUA:10 a=6I5d2MoRAAAA:8 a=BWvPGDcYAAAA:8 a=YxBL1-UpAAAA:8 a=VJNF8P6jpN-Z4JSqVdwA:9 a=CjuIK1q_8ugA:10 a=IjZwj45LgO3ly-622nXo:22 a=pxhY87DP9d2VeQe4joPk:22 a=Ia-lj3WSrqcvXOmTRaiG:22 Received: from slippy.cwsent.com (slippy [10.1.1.91]) by spqr.komquats.com (Postfix) with ESMTPS id 8FF021E76; Sat, 19 Aug 2017 12:50:26 -0700 (PDT) Received: from slippy (localhost [127.0.0.1]) by slippy.cwsent.com (8.15.2/8.15.2) with ESMTP id v7JJoQiH003322; Sat, 19 Aug 2017 12:50:26 -0700 (PDT) (envelope-from Cy.Schubert@cschubert.com) Message-Id: <201708191950.v7JJoQiH003322@slippy.cwsent.com> X-Mailer: exmh version 2.8.0 04/21/2012 with nmh-1.6 Reply-to: Cy Schubert From: Cy Schubert X-os: FreeBSD X-Sender: cy@cwsent.com X-URL: http://www.cschubert.com/ To: David Chisnall cc: Cy Schubert , tech-lists , freebsd-current@freebsd.org Subject: Re: swapfile query In-Reply-To: Message from David Chisnall of "Sat, 19 Aug 2017 18:03:01 +0100." Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Sat, 19 Aug 2017 12:50:26 -0700 X-CMAE-Envelope: MS4wfLVTC5ph/O1ykN6b3we4PSkm+bMTJyLRKpN2obOom4/mNuuCQSRZJNp+nZM3BN39pUAUxZKB04P67gh5CrwY1jk6FhDxt559pCJJng4o7eOkPdC4ln5p /WQVwUSfSfInwxKPN2jZ+J90LfrrzY/Ys/FdYgtys36trjDw1KJ0OkhATiA3+pW9rl5lZ6oPaI8aqlQeM1ST51F8SI3h0JVN6Mv78IGzTbOi6bRNBHcQPfYq L9Bm1h+ijGjFr91ugqDvSw== X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 19 Aug 2017 19:50:30 -0000 In message , David Chisnall w rites: > On 19 Aug 2017, at 17:54, Cy Schubert wrote: > > > >> 3. should total swap be 1x 2x or some other multiple of RAM these days? > > > > Depends. If you're running some kind of database server or OLTP > > application. Some vendors recommend no swap whatsoever while others > > recommend some. What does your application vendor recommend? > > The main advantage of swap these days (on machines with that sort of amount o > f RAM) is to allow you to keep some file-backed memory objects in memory in p > reference to leaked (or very cold) heap memory. Memory overcommitment and the working set of each address space determines how much and what is paged out. -- Cheers, Cy Schubert FreeBSD UNIX: Web: http://www.FreeBSD.org The need of the many outweighs the greed of the few.