From owner-freebsd-fs@FreeBSD.ORG Tue Jan 13 22:30:57 2015 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 860B8FE8; Tue, 13 Jan 2015 22:30:57 +0000 (UTC) Received: from hergotha.csail.mit.edu (wollman-1-pt.tunnel.tserv4.nyc4.ipv6.he.net [IPv6:2001:470:1f06:ccb::2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 2994D816; Tue, 13 Jan 2015 22:30:56 +0000 (UTC) Received: from hergotha.csail.mit.edu (localhost [127.0.0.1]) by hergotha.csail.mit.edu (8.14.9/8.14.9) with ESMTP id t0DMUsQx061186; Tue, 13 Jan 2015 17:30:54 -0500 (EST) (envelope-from wollman@hergotha.csail.mit.edu) Received: (from wollman@localhost) by hergotha.csail.mit.edu (8.14.9/8.14.4/Submit) id t0DMUs2c061183; Tue, 13 Jan 2015 17:30:54 -0500 (EST) (envelope-from wollman) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Message-ID: <21685.40094.453028.585630@hergotha.csail.mit.edu> Date: Tue, 13 Jan 2015 17:30:54 -0500 From: Garrett Wollman To: freebsd-fs@freebsd.org, freebsd-stable@freebsd.org Subject: Some filesystem performance numbers X-Mailer: VM 7.17 under 21.4 (patch 22) "Instant Classic" XEmacs Lucid X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.4.3 (hergotha.csail.mit.edu [127.0.0.1]); Tue, 13 Jan 2015 17:30:55 -0500 (EST) X-Spam-Status: No, score=-1.0 required=5.0 tests=ALL_TRUSTED, HEADER_FROM_DIFFERENT_DOMAINS autolearn=disabled version=3.4.0 X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on hergotha.csail.mit.edu X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 13 Jan 2015 22:30:57 -0000 I recently bought a copy of the SPECsfs2014 benchmark, and I've been using it to test out our NFS server platform. One scenario of interest to me is identifying where the limits are in terms of the local CAM/storage/filesystem implementation versus bottlenecks unique to the NFS server, and to that end I've been running the benchmark suite directly on the server's local disk. (This is of course also the way you'd benchmark for shared-nothing container-based virtualization.) I have found a few interesting results on my test platform: 1) I can quantify the cost of using SHA256 vs. fletcher4 as the ZFS checksum algorithm. On the VDA workload (essentially a simulated video streaming/recording application), my server can do about half as many "streams" with SHA256 as it can with fletcher4. 2) Both L2ARC and separate ZIL have small but measurable performance impacts. I haven't examined the differences closely. 3) LZ4 compression also makes a small performance impact, but as advertised, less than LZJB for mostly-incompressible data. I hope to be able to present the actual benchmark results at some point, as well as some results for the other three workloads. -GAWollman