From owner-freebsd-current@FreeBSD.ORG Mon Dec 19 21:00:23 2011 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id ED0591065675 for ; Mon, 19 Dec 2011 21:00:23 +0000 (UTC) (envelope-from se@freebsd.org) Received: from nm12.bullet.mail.bf1.yahoo.com (nm12.bullet.mail.bf1.yahoo.com [98.139.212.171]) by mx1.freebsd.org (Postfix) with SMTP id 776538FC15 for ; Mon, 19 Dec 2011 21:00:23 +0000 (UTC) Received: from [98.139.212.146] by nm12.bullet.mail.bf1.yahoo.com with NNFMP; 19 Dec 2011 21:00:22 -0000 Received: from [98.139.213.15] by tm3.bullet.mail.bf1.yahoo.com with NNFMP; 19 Dec 2011 21:00:22 -0000 Received: from [127.0.0.1] by smtp115.mail.bf1.yahoo.com with NNFMP; 19 Dec 2011 21:00:22 -0000 X-Yahoo-Newman-Id: 591539.5237.bm@smtp115.mail.bf1.yahoo.com X-Yahoo-Newman-Property: ymail-3 X-YMail-OSG: 4VXzduwVM1lvKFUnABLpb.zdxRUFlbQhXuwi5r2GxkLzQo5 QuG2Pr2iSI9oP8x_bOax3blTtg_ftA4tsxoGY7QvBtjRkpFAyrzCdUZpciSR BsY9UsTULR6tS4YrALt6OlrF8EgO4LYypYdEmKVmN_BgoepcX9JtTMNhygiT 4m4uvJEanF5qeT4VZhG6iOLkmgYXQBkBdTyX2JVYzFRXH8aNrctcxdGGWxCU 6FVP4pDaRqqR_4V06wvk66OxN04ettoCxHr.l7ZUYBdcGCprmEa8QSI6NDwu urUHv6VmgYkjU8bT5rAQ8onwjaWhRyHIL6WvBclYm06t8Ke1Ce1XDL7UtBfV rcFe_11aN0.LilkD8ebQ0ee86wNqMOXcwyKh_YTOJV94tMwAP3nHZ04eQ_oA vHVN6_h7aA9FAmhw3 X-Yahoo-SMTP: iDf2N9.swBDAhYEh7VHfpgq0lnq. Received: from [192.168.119.20] (se@81.173.146.234 with plain) by smtp115.mail.bf1.yahoo.com with SMTP; 19 Dec 2011 13:00:22 -0800 PST Message-ID: <4EEFA5E4.9070803@freebsd.org> Date: Mon, 19 Dec 2011 22:00:20 +0100 From: Stefan Esser User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:8.0) Gecko/20111105 Thunderbird/8.0 MIME-Version: 1.0 To: Daniel Kalchev References: <4EEF488E.1030904@freebsd.org> <83648C73-E45F-4ABA-8E83-4C8903A683AB@digsys.bg> In-Reply-To: <83648C73-E45F-4ABA-8E83-4C8903A683AB@digsys.bg> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: FreeBSD Current Subject: Re: Uneven load on drives in ZFS RAIDZ1 X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 19 Dec 2011 21:00:24 -0000 Am 19.12.2011 19:03, schrieb Daniel Kalchev: > I have observed similar behavior, even more extreme on a spool with dedup enabled. Is dedup enabled on this spool? Thank you for the report! Well, I had dedup enabled for a few short tests. But since I have got "only" 8GB of RAM and dedup seems to require an order of magnitude more to be working well, I switched dedup off again after a few hours. > Might be that the DDT tables somehow end up unevenly distributed to disks. My observation was on a 6 disk raidz2. Hmmm, there was another report of even distribution of load on a 6 disk raidz1 (but in fact, in that case the first half seems to have got some 10% to 15 higher load than the second half; the sixth drive showed quite different queue length and latencies and I think these might be caused either by a defect (soft-errors) or another partition being actively used only on that drive). Regards, STefan