From owner-freebsd-fs@FreeBSD.ORG Thu May 19 16:56:56 2011 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id 03139106564A for ; Thu, 19 May 2011 16:56:56 +0000 (UTC) (envelope-from piotr.kucharski@42.pl) Received: from mail-ew0-f54.google.com (mail-ew0-f54.google.com [209.85.215.54]) by mx1.freebsd.org (Postfix) with ESMTP id 8BBBB8FC14 for ; Thu, 19 May 2011 16:56:55 +0000 (UTC) Received: by ewy1 with SMTP id 1so1284501ewy.13 for ; Thu, 19 May 2011 09:56:54 -0700 (PDT) Received: by 10.204.73.206 with SMTP id r14mr1284954bkj.181.1305822609153; Thu, 19 May 2011 09:30:09 -0700 (PDT) MIME-Version: 1.0 Received: by 10.204.38.137 with HTTP; Thu, 19 May 2011 09:29:29 -0700 (PDT) X-Originating-IP: [224.9.88.219] In-Reply-To: References: From: Piotr Kucharski Date: Thu, 19 May 2011 18:29:29 +0200 Message-ID: To: Adam Vande More Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Cc: freebsd-fs@freebsd.org Subject: Re: very slow zfs scrub X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 19 May 2011 16:56:56 -0000 On Thu, Feb 24, 2011 at 21:00, Adam Vande More wrot= e: >> Wow! What does scrub do that it slows ggate drive almost to halt? >> >> What can I do to fix it? > > I think network latency is going to have huge impact on performance here. > Have you tried any ggate or nic tuning?=C2=A0 Would HAST be an option for= you?=C2=A0 I > think it has more performance thought put into it. > Well, the network seems rather idle, host and client share the same 1Gb LAN (not sure if the same switch, though) with <0.2ms rtt for 1k packets in ping. When not scrubbing, sequential reads are satisfactory. I'm inclined to think some read or write pattern of scrub that is causing ggate to suck immensely. :/