From owner-freebsd-questions@FreeBSD.ORG  Wed Sep 14 19:44:55 2005
Return-Path: <owner-freebsd-questions@FreeBSD.ORG>
X-Original-To: freebsd-questions@freebsd.org
Delivered-To: freebsd-questions@freebsd.org
Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125])
	by hub.freebsd.org (Postfix) with ESMTP id 3539216A41F
	for <freebsd-questions@freebsd.org>;
	Wed, 14 Sep 2005 19:44:55 +0000 (GMT)
	(envelope-from dmarshall@gmail.com)
Received: from rproxy.gmail.com (rproxy.gmail.com [64.233.170.203])
	by mx1.FreeBSD.org (Postfix) with ESMTP id A518443D49
	for <freebsd-questions@freebsd.org>;
	Wed, 14 Sep 2005 19:44:54 +0000 (GMT)
	(envelope-from dmarshall@gmail.com)
Received: by rproxy.gmail.com with SMTP id i8so11686rne
	for <freebsd-questions@freebsd.org>;
	Wed, 14 Sep 2005 12:44:53 -0700 (PDT)
DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com;
	h=received:message-id:date:from:reply-to:to:subject:mime-version:content-type:content-transfer-encoding:content-disposition;
	b=puFKSiJl3Rvhb0qaQPxJKlmP+caSxz6qha6oAX2RHJCNQM1BWwQKJ1q2vkt59A8C5sBXC6P2jHKhQ91/8BDHT5dtHSacVcaR3X5UID2wQNSvOMD61PamPnG5m+CcoR1ioWrWqgC2HKTi/NEVjp/nIM+oys/Qkjgx58nMIr2yj5o=
Received: by 10.38.208.66 with SMTP id f66mr223476rng;
	Wed, 14 Sep 2005 12:44:53 -0700 (PDT)
Received: by 10.38.181.14 with HTTP; Wed, 14 Sep 2005 12:44:53 -0700 (PDT)
Message-ID: <53f1586305091412443a993251@mail.gmail.com>
Date: Wed, 14 Sep 2005 12:44:53 -0700
From: David Marshall <dmarshall@gmail.com>
To: freebsd-questions@freebsd.org
Mime-Version: 1.0
Content-Type: text/plain; charset=ISO-8859-1
Content-Transfer-Encoding: quoted-printable
Content-Disposition: inline
Subject: File-Backed Memory Disks: Performance and Manipulation
X-BeenThere: freebsd-questions@freebsd.org
X-Mailman-Version: 2.1.5
Precedence: list
Reply-To: dmarshall@gmail.com
List-Id: User questions <freebsd-questions.freebsd.org>
List-Unsubscribe: <http://lists.freebsd.org/mailman/listinfo/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: Wed, 14 Sep 2005 19:44:55 -0000

Hi,

Scenario: We have millions of little (almost all < 10 kB), about 30 GB
total.  It takes > 24 hours to either tar them up or then untar them.=20
It finally occured to us to put them into a file-backed memory disk.

Questions:

1. How does the performance of a file-backed memory disk change as it
becomes large?

2. Is there a clever way to make such a file-backed memory disk bigger
after the fact?  If I want to expand my 30 GB file to 50 GB, am I
stuck with just making a new one and copying it over?

TIA!