From owner-freebsd-questions@freebsd.org Thu Mar 26 09:22:05 2020 Return-Path: Delivered-To: freebsd-questions@mailman.nyi.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2610:1c1:1:606c::19:1]) by mailman.nyi.freebsd.org (Postfix) with ESMTP id 543572799CC for ; Thu, 26 Mar 2020 09:22:05 +0000 (UTC) (envelope-from freebsd@qeng-ho.org) Received: from bede.qeng-ho.org (bede.qeng-ho.org [217.155.128.241]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) server-signature RSA-PSS (4096 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 48nzyM72DVz41Dj for ; Thu, 26 Mar 2020 09:21:47 +0000 (UTC) (envelope-from freebsd@qeng-ho.org) Received: from arthur.home.qeng-ho.org (arthur.home.qeng-ho.org [172.23.1.2]) by bede.qeng-ho.org (Postfix) with ESMTP id 74A511035E; Thu, 26 Mar 2020 09:14:32 +0000 (GMT) Subject: Re: drive selection for disk arrays To: David Christensen , freebsd-questions@freebsd.org References: <20200325081814.GK35528@mithril.foucry.net> <713db821-8f69-b41a-75b7-a412a0824c43@holgerdanske.com> From: Arthur Chance Message-ID: <24b684fe-35c4-5959-b02a-7c3ac1df3477@qeng-ho.org> Date: Thu, 26 Mar 2020 09:14:32 +0000 User-Agent: Mozilla/5.0 (X11; FreeBSD amd64; rv:68.0) Gecko/20100101 Thunderbird/68.3.1 MIME-Version: 1.0 In-Reply-To: <713db821-8f69-b41a-75b7-a412a0824c43@holgerdanske.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Rspamd-Queue-Id: 48nzyM72DVz41Dj X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; dkim=none; dmarc=none; spf=pass (mx1.freebsd.org: domain of freebsd@qeng-ho.org designates 217.155.128.241 as permitted sender) smtp.mailfrom=freebsd@qeng-ho.org X-Spamd-Result: default: False [-4.78 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-1.000,0]; FROM_HAS_DN(0.00)[]; TO_DN_SOME(0.00)[]; R_SPF_ALLOW(-0.20)[+ip4:217.155.128.240/29]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; MIME_GOOD(-0.10)[text/plain]; RCVD_TLS_LAST(0.00)[]; DMARC_NA(0.00)[qeng-ho.org]; TO_MATCH_ENVRCPT_SOME(0.00)[]; RCPT_COUNT_TWO(0.00)[2]; IP_SCORE(-2.48)[ip: (-7.73), ipnet: 217.155.0.0/16(-3.87), asn: 13037(-0.74), country: GB(-0.07)]; FROM_EQ_ENVFROM(0.00)[]; R_DKIM_NA(0.00)[]; MIME_TRACE(0.00)[0:+]; ASN(0.00)[asn:13037, ipnet:217.155.0.0/16, country:GB]; MID_RHS_MATCH_FROM(0.00)[]; RCVD_COUNT_TWO(0.00)[2] X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 26 Mar 2020 09:22:05 -0000 On 25/03/2020 22:19, David Christensen wrote: > Jacques Foucry wrote: > >> ALWAYS (when it's possible) buy and use disks from different brand >> (mix seagate, WD, etc..) in order to avoid same series and same MTBF. >> >> I know this to late in this case, but keep this in mind. >> >> I know this will not help in this case, please excuse my >> intervention if it's inappropriate. > > > To date, most of my arrays have been composed of similar drives.  But, I > run a SOHO LAN and have limited experience.  I have been wondering about > using dissimilar drives to prevent simultaneous common-mode failures. > > > Backblaze publishes statistics for individual drives: > > https://www.backblaze.com/blog/hard-drive-stats-q2-2019/ > > > I would be curious to read any data or reports comparing arrays of > similar drives vs. arrays of dissimilar drives. > > > Have anyone seen a failure involving multiple similar drives all failing > in the same mode at the same time? Not at exactly the same time, but the first time I ever built a zraid array, shortly after zfs was first released, I used a batch of four identical disks. About 5-6 years later they all failed over a period of about 2-3 months. There was long enough between failures to buy a replacement drive on next day delivery and recover, but this was on a home file server, not a heavily loaded system. Nowadays I buy from a couple of manufacturers based on Backblaze's latest statistics. -- Violets are red And roses are blue When metamaterials Alter their hue.