From owner-freebsd-jail@freebsd.org Sun Feb 19 11:56:35 2017 Return-Path: Delivered-To: freebsd-jail@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 46AF8CE5C50 for ; Sun, 19 Feb 2017 11:56:35 +0000 (UTC) (envelope-from lists@opsec.eu) Received: from home.opsec.eu (home.opsec.eu [IPv6:2001:14f8:200::1]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 0D40E1B3B for ; Sun, 19 Feb 2017 11:56:35 +0000 (UTC) (envelope-from lists@opsec.eu) Received: from pi by home.opsec.eu with local (Exim 4.87 (FreeBSD)) (envelope-from ) id 1cfQ6T-000FFj-NY; Sun, 19 Feb 2017 12:56:33 +0100 Date: Sun, 19 Feb 2017 12:56:33 +0100 From: Kurt Jaeger To: Nikos Vassiliadis Cc: freebsd-jail@freebsd.org Subject: Re: unionfs and nullfs combination Message-ID: <20170219115633.GW13006@home.opsec.eu> References: <72a56f7e-8e71-2b98-0978-6de863013ce5@gmx.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <72a56f7e-8e71-2b98-0978-6de863013ce5@gmx.com> X-BeenThere: freebsd-jail@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: "Discussion about FreeBSD jail\(8\)" List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sun, 19 Feb 2017 11:56:35 -0000 Hi! > One relatively cheap way to create thin jails in the pre-ZFS era, > was to combine nullfs and unionfs (1). This seem to work only in > 10 and previous branches. Do you use such a combination? We had this running with FreeBSD 6.x, but unionfs had issues, among them the whiteout problem. If you have a directory where many small files with random names are created in the upper layer, and deleted afterwards, the directory in the upper layer grows with each file because of the way whiteout files are handled. There's a mount option whiteout=whenneeded that should fix this, I no longer remember what stopped us from using it. > It seems like a very relevant feature nowadays, when people > use all these cloud-based systems, which oftentimes have little > resources to run ZFS and UFS is most likely a better choice... Funny, I have the impression that disk space, RAM and CPU are plenty compared to the past, so I would prefer ZFS anytime now. Our next jail box will probably use ZFS dedup with lots of RAM. -- pi@opsec.eu +49 171 3101372 3 years to go !