From owner-freebsd-questions@FreeBSD.ORG Sun Aug 31 17:12:40 2014 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [8.8.178.115]) (using TLSv1 with cipher ADH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id AF7ABF26 for ; Sun, 31 Aug 2014 17:12:40 +0000 (UTC) Received: from mail-qc0-f171.google.com (mail-qc0-f171.google.com [209.85.216.171]) (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 61BDC1E36 for ; Sun, 31 Aug 2014 17:12:39 +0000 (UTC) Received: by mail-qc0-f171.google.com with SMTP id x3so4437244qcv.2 for ; Sun, 31 Aug 2014 10:12:33 -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=6C5F+FwjtXZ3VSgPNGiYYj9Z/ZohfPxFhBaTm0Np78c=; b=L7WSZpM0kBqxcU1MKT/Zd3ookMKlz2zvww3465VN7e6dRi9wIt670U8nLfCYnNZQ2P iBNYEFgR9yw9zF7GuOKT/IaQu5WWRWucJJD9yYM77fD15oGkUNF1kAG8AVMvffWkqE/w KSquJIHQkMRcKFldzMYkg506BmVLaEar6m5Iq30mMBaErsRESwWeGR6frZW2BWfEZObM NNN81ZqXNs4vBabgNEvb/cJtmC4eU0DCITjvXT8/I1HDcnjOi9J+IgAfJYZ7PONOlUpz 61QT4amm75EDfj1FGdX33tx9gIqX1Xrk2972bli2oqgq5zhWSA73oAB9d5IcQPyBGr5S QNSA== X-Gm-Message-State: ALoCoQks57APIWVv12n5OAjpumvfSwPEomh4J2se1Np69Fklnvzq3/DfcCxHHpE4uf437gKd4eI1 X-Received: by 10.229.73.70 with SMTP id p6mr37580242qcj.13.1409505153717; Sun, 31 Aug 2014 10:12:33 -0700 (PDT) Received: from [192.168.2.65] ([96.236.21.80]) by mx.google.com with ESMTPSA id w9sm18993045qad.31.2014.08.31.10.12.32 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Sun, 31 Aug 2014 10:12:32 -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: <201408310749.s7V7nVsf025094@sdf.org> Date: Sun, 31 Aug 2014 13:12:32 -0400 Content-Transfer-Encoding: quoted-printable Message-Id: 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> <58E30C52-A12C-4D9E-95D6-5BFB7A05FE46@kraus-haus.org> <201408310749.s7V7nVsf025094@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: Sun, 31 Aug 2014 17:12:40 -0000 On Aug 31, 2014, at 3:49, Scott Bennett wrote: > Paul Kraus wrote: >> I typically run a scrub on any new drive after writing a bunch of = data to it, specifically to look for infant mortality :-) >=20 > Looks like a good idea. Whenever I get the raidz2 set up and some > sizable amount of data loaded into it, I intend to do the same. = However, > because the capacity of the 6-drive raidz2 will be about four times = the > original UFS2 capacity, I suppose I'll need to find a way to expand = the > dump file in other ways, so as to cover the misbehaving tracks on the > individual drives. I=92m not sure I would worry about exercising the entire range of tracks = on the platters, if a platter has a problem (heads or coating) it will = likely show up all over the platter. If the problem is specific to a = region, I would expect the drive to be able to remap the bad sectors (as = we previously discussed). >> Don?t go by what *I* say, go the manufacturer?s 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. >=20 > Yes, I understood that from what you had already written. What I = meant > was that I hadn't been aware that the manufacturers were selling the = drives > divided into two differing grades of reliability. =46rom now on, the = issue > will be a matter of my budget vs. the price differences. Sorry If I was being overly descriptive, I am more of a math and science = guy than an english guy, so my writing is often not the most clear. When = I started buying Enterprise instead of Desktop drives the price = difference was under $20 for a $100 drive. The biggest reason I started = buying the Enterprise drives is that they are RATED for 24x7 operation, = while Desktop are typically designed for 8x5 (but rarely do they say :-) = While I do have my desktop and laptop systems setup to spin down the = drives when not in use (and I leave some of them booted 24x7), my = server(s) run 24x7 and THAT is where I pay for the Enterprise drives. I = treat the drives in the laptop / desktop systems as disposable and do = NOT keep any important data only on them (I rsync my laptop to the = server a couple times per week and use TimeMachine when at the office). > Okay. Thanks again for the info. Just out of curiosity, where do = you > usually find those Hitachi drives? Newegg =85 Once they lean red how to ship drives without destroying them = I started buying drives from them :-) >> I wonder if it an issue with a single file larger than 1TB ? just = wondering out loud here. >=20 > Well, all I can say is that it is not supposed to be. After all, = file > systems that were very large were the reason for going from UFS1 to = UFS2. I realized that I proposed something ludicrous (the problem with = thinking =93aloud=94), if the FS did not support -files- larger than = 1TB, then the write operation would have failed when you got to that = point. Yes, I remember FSes that could not handle a -file- larger than = 2GB! Note that there is a difference between the size of a filesystem and the = size of the largest -file- that filesystem may contain. >> 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. >>=20 > I would count yourself very lucky if I were you, although my = previous > remark regarding the difference in reliability grades still holds. I have not tried to use Desktop drives in a Servers (either my own or a = client=92s) for well over a decade. I do not remember much about drive = failures before that. Back then my need for capacity was growing faster = than drives were failing, so I was upgrading before the drives failed. I = still have a pile of 9GB SCSI drives (and some 18GB and 36GB) kicking = around from those days. Not to mention the drawer full of 500MB (yes, = 0.5GB) drives I harvested from an old Sun SS1000 before I sold it =85 I = should have left the drives in it. -- Paul Kraus paul@kraus-haus.org