From owner-freebsd-questions@FreeBSD.ORG  Tue Jul 22 16:24:15 2014
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115])
 (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits))
 (No client certificate requested)
 by hub.freebsd.org (Postfix) with ESMTPS id A7000165
 for <freebsd-questions@freebsd.org>; Tue, 22 Jul 2014 16:24:15 +0000 (UTC)
Received: from wonkity.com (wonkity.com [67.158.26.137])
 (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
 (Client CN "wonkity.com", Issuer "wonkity.com" (not verified))
 by mx1.freebsd.org (Postfix) with ESMTPS id 50F8B28D3
 for <freebsd-questions@freebsd.org>; Tue, 22 Jul 2014 16:24:14 +0000 (UTC)
Received: from wonkity.com (localhost [127.0.0.1])
 by wonkity.com (8.14.9/8.14.9) with ESMTP id s6MGOD5c083377
 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=NO);
 Tue, 22 Jul 2014 10:24:13 -0600 (MDT)
 (envelope-from wblock@wonkity.com)
Received: from localhost (wblock@localhost)
 by wonkity.com (8.14.9/8.14.9/Submit) with ESMTP id s6MGODMB083374;
 Tue, 22 Jul 2014 10:24:13 -0600 (MDT)
 (envelope-from wblock@wonkity.com)
Date: Tue, 22 Jul 2014 10:24:13 -0600 (MDT)
From: Warren Block <wblock@wonkity.com>
To: Arthur Chance <freebsd@qeng-ho.org>
Subject: Re: How much swap space for a 32 GB RAM system?
In-Reply-To: <53CE8BB8.7030303@qeng-ho.org>
Message-ID: <alpine.BSF.2.11.1407221018190.80885@wonkity.com>
References: <53CE8BB8.7030303@qeng-ho.org>
User-Agent: Alpine 2.11 (BSF 23 2013-08-11)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed
X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3
 (wonkity.com [127.0.0.1]); Tue, 22 Jul 2014 10:24:13 -0600 (MDT)
Cc: FreeBSD-Questions <freebsd-questions@freebsd.org>
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.18
Precedence: list
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/options/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=unsubscribe>
List-Archive: <http://lists.freebsd.org/pipermail/freebsd-questions/>
List-Post: <mailto:freebsd-questions@freebsd.org>
List-Help: <mailto:freebsd-questions-request@freebsd.org?subject=help>
List-Subscribe: <http://lists.freebsd.org/mailman/listinfo/freebsd-questions>, 
 <mailto:freebsd-questions-request@freebsd.org?subject=subscribe>
X-List-Received-Date: Tue, 22 Jul 2014 16:24:15 -0000

On Tue, 22 Jul 2014, Arthur Chance wrote:

> I'm getting a new machine with 32 GB of memory. The old "twice physical 
> memory" sizing seems ridiculous, so how big should I make swap? Do I even 
> need swap with this much memory?

Technically, no, but the system does like to have at least a little swap 
space and can benefit from it.  (I forget where this is explained, 
tuning(7) maybe.)

How much swap to allocate depends on the use of the system.  On 
desktop-type systems where I'd normally not expect swap to be needed, I 
usually use 4G as a size large enough to be useful if it is ever needed 
but not so big as to make a noticeable dent in disk usage.