From owner-freebsd-questions@FreeBSD.ORG Wed Sep 14 19:38:58 2011 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 2C5D4106566B for ; Wed, 14 Sep 2011 19:38:58 +0000 (UTC) (envelope-from rwmaillists@googlemail.com) Received: from mail-wy0-f182.google.com (mail-wy0-f182.google.com [74.125.82.182]) by mx1.freebsd.org (Postfix) with ESMTP id B50F98FC08 for ; Wed, 14 Sep 2011 19:38:57 +0000 (UTC) Received: by wyh15 with SMTP id 15so2622797wyh.13 for ; Wed, 14 Sep 2011 12:38:56 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=date:from:to:subject:message-id:in-reply-to:references:x-mailer :mime-version:content-type:content-transfer-encoding; bh=qSsND1E2JiVlxJweEiEMD47VIczgSWsMtx8hm4huhks=; b=uBT/x7uM7zoNi1Jc4OG7+Kox4hMYvgRAXtNY92UTbNJUaqcqCn3bpxg6/V158xSXHj bRofeP1lrSpuAs4nvX973WIBdpqkE3PlGpN+CJbwef8K+pW6RiMES1nvSF+E541Skc29 wQjx30FKiJKAurtsEJJGDh80F2UcGibdG/o/I= Received: by 10.227.6.11 with SMTP id 11mr224120wbx.87.1316029136691; Wed, 14 Sep 2011 12:38:56 -0700 (PDT) Received: from gumby.homeunix.com (87-194-105-247.bethere.co.uk. [87.194.105.247]) by mx.google.com with ESMTPS id r27sm5202517wbn.10.2011.09.14.12.38.54 (version=SSLv3 cipher=OTHER); Wed, 14 Sep 2011 12:38:55 -0700 (PDT) Date: Wed, 14 Sep 2011 20:38:51 +0100 From: RW To: freebsd-questions@freebsd.org Message-ID: <20110914203851.41fa717a@gumby.homeunix.com> In-Reply-To: <4E70B269.4020900@infracaninophile.co.uk> References: <4E709F62.60705@gmail.com> <4E70B269.4020900@infracaninophile.co.uk> X-Mailer: Claws Mail 3.7.10 (GTK+ 2.24.6; amd64-portbld-freebsd8.2) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Subject: Re: Recommended SWAP space for large amounts of ram (8GB) 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, 14 Sep 2011 19:38:58 -0000 On Wed, 14 Sep 2011 14:55:53 +0100 Matthew Seaman wrote: > On 14/09/2011 13:34, Jonathan Vomacka wrote: > > Either from the FreeBSD docs, or based on personal experiences, > > what is the recommended swap space for a 8GB system? Your opinions > > are greatly appreciated > > The old rule of thumb of swap = 2 x RAM dates back to the days when > 128MB RAM was a big deal. Nowadays, you're likely to have that much > in your phone, and systems with 128GB RAM are not unknown. > > In these days of plentiful RAM, the new rule of thumb is "if you're > swapping, then you're doing it wrong." There is a caveat that on desktop grade motherboards, expanding beyond 8GB can slow the system down, as populating 4 slots can cause the memory to run at a slower speed. > My recommendation: for systems with 1GB RAM or more, and that don't > make heavy use of memory filesystems and the like, then 2GB swap is > ample, and you can probably get away with as little as 1GB at need. If you have 8GB of ram and you can get away with 1GB of swap, then you presumably could get away with none. This question recently came up on "hackers", and someone posted top output from a 12GB system showing a 23GB openoffice process and 21GB of swap in use after opening a large spreadsheet file. I think there's a reasonable case for providing enough swap to cope with abnormal memory use.