From owner-freebsd-questions@FreeBSD.ORG Sat Aug 30 23:07:43 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id C83608A4 for ; Sat, 30 Aug 2014 23:07:43 +0000 (UTC) Received: from mail-qa0-f49.google.com (mail-qa0-f49.google.com [209.85.216.49]) (using TLSv1 with cipher ECDHE-RSA-RC4-SHA (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id 7CCB21512 for ; Sat, 30 Aug 2014 23:07:42 +0000 (UTC) Received: by mail-qa0-f49.google.com with SMTP id i13so3610685qae.36 for ; Sat, 30 Aug 2014 16:07:36 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:subject:mime-version:content-type:from :in-reply-to:date:cc:content-transfer-encoding:message-id:references :to; bh=5yR01Ddy4BEJ5DzkaTDS8E4/Hv8VyiH/Ef/A0aD4Hbc=; b=RDuQiW3sdz3D2I77nHcPh2DSup1Dqk+lGrEUc8D1JEFUDGDKW22Rewu8ZJCkVsTQ89 WaZCRU/I+nS3BhsfKf1ODJlq9Wy3X+exMyZZ3UsJExOI9hG2NBQIKfxrBFRNWua7lP3o PLw35+KowjqBoc4gRLeZ/TegxzHfKpBFkahnpEIeiQpcykAkZ4RNiGnWY7AMUBnQgJFu mQrkJoNsP5AADLzn0E7j5tL6Ni8DuLglh/i97RKXVhZ85yetFJciga0MJLWqbk/Lho5e gfu2f4S+8o7wOftUkGGj0U9NYYcou9ffplXtXjlhbUjSQEwtnDceT3beLZY7faeBcUoE x9OA== X-Gm-Message-State: ALoCoQldGCLqXtLCyPjV//9gl33gJDaylYUSV7PJXVJVHmtF48QWHNVSxLagsEnvQx5tWbi0jKZu X-Received: by 10.140.31.75 with SMTP id e69mr11048853qge.2.1409439633644; Sat, 30 Aug 2014 16:00:33 -0700 (PDT) Received: from [192.168.2.65] ([96.236.21.80]) by mx.google.com with ESMTPSA id d8sm12412146qam.46.2014.08.30.16.00.32 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sat, 30 Aug 2014 16:00:33 -0700 (PDT) Subject: Re: gvinum raid5 vs. ZFS raidz Mime-Version: 1.0 (Mac OS X Mail 7.3 \(1878.6\)) Content-Type: text/plain; charset=windows-1252 From: Paul Kraus In-Reply-To: <201408300147.s7U1leJP024616@sdf.org> Date: Sat, 30 Aug 2014 19:00:32 -0400 Content-Transfer-Encoding: quoted-printable Message-Id: <58E30C52-A12C-4D9E-95D6-5BFB7A05FE46@kraus-haus.org> References: <201408020621.s726LsiA024208@sdf.org> <53DCDBE8.8060704@qeng-ho.org> <201408060556.s765uKJA026937@sdf.org> <53E1FF5F.1050500@qeng-ho.org> <201408070831.s778VhJc015365@sdf.org> <201408070936.s779akMv017524@sdf.org> <201408071106.s77B6JCI005742@sdf.org> <5B99AAB4-C8CB-45A9-A6F0-1F8B08221917@kraus-haus.org> <201408220940.s7M9e6pZ008296@sdf.org> <7971D6CA-AEE3-447D-8D09-8AC0B9CC6DBE@kraus-haus.org> <201408260641.s7Q6feBc004970@sdf.org> <9588077E-1198-45AF-8C4A-606C46C6E4F8@kraus-haus.org> <201408280636.s7S6a5OZ022667@sdf.org> <25B567A0-6639-41EE-AB3E-96AFBA3F11B7@kraus-haus.org> <201408300147.s7U1leJP024616@sdf.org> To: Scott Bennett X-Mailer: Apple Mail (2.1878.6) Cc: freebsd-questions@freebsd.org, freebsd@qeng-ho.org, Trond.Endrestol@fagskolen.gjovik.no X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 30 Aug 2014 23:07:43 -0000 On Aug 29, 2014, at 21:47, Scott Bennett wrote: > Paul Kraus wrote: >> I have been testing with a bunch of 2TB (3 HGST and 1 WD). I have = been using ZFS and it has not reported *any* checksum errors. >>=20 > What sort of testing? Unless the data written with errors are = read back, > how would ZFS know about any checksum errors? Does ZFS implement = write-with- > verify? Copying some humongous file and then reading it back for = comparison > (or, with ZFS, just reading them) ought to bring the checksums into = play. Of > course, a scrub should do that, too. I typically run a scrub on any new drive after writing a bunch of data = to it, specifically to look for infant mortality :-) > I have never bought the enterprise-grade drives--though I may = begin doing > so after having read the information you've brought up here--so the = difference > in drive quality at the outset may explain why your results so far = have been > so much better than mine. Don=92t go by what *I* say, go the manufacturer=92s web sites and = download and read the full specifications on the drives you are looking = at. None of the sales sites (Newegg, CDW, etc.) post the full specs, yet = they are all (still) available from the Seagate / Western Digital / HGST = etc. web sites. I am just starting to play with a different WD Enterprise series, so far = all my testing (and use) has been with the RE series, I just got two 1TB = SE series (which are also 5 year warranty and claim to be Enterprise = grade, rated for 24x7 operation). I put them into service today and = expect to be loading data on them tomorrow or Monday. So now I will have = Seagate ES, ES.2, HGST Ultrastar (various P/N), and WD RE, SE drives in = use. >>> If so, try copying a 1.1 TB >>> file to one of them, and then trying comparing the copy against the = original. >>=20 >> Hurmmm. I have not worked with individual files that large. What = filesystem are you using here?=20 >=20 > At the moment, all of my file systems on hard drives are UFS2. I wonder if it an issue with a single file larger than 1TB =85 just = wondering out loud here. > My expectation is that I will end up contacting one or more = manufacturers > to try to replace at least two drives based on whatever ZFS detects, = but I > would be glad to be mistaken about that for now. If two are that bad, = then > I hope that ZFS can keep things running until the replacements show up = here. I have never had to warranty a drive for uncorrectable errors, they have = been a small enough percentage that I did not worry about them, and when = the error rate gets big enough other things start going wrong as well. = At least that has been my experience. -- Paul Kraus paul@kraus-haus.org