From owner-freebsd-questions@freebsd.org Thu Mar 26 18:57:56 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 A100D2A6F47 for ; Thu, 26 Mar 2020 18:57:56 +0000 (UTC) (envelope-from bob@proulx.com) Received: from havoc.proulx.com (havoc.proulx.com [96.88.95.61]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 48pDkv36Llz4TM6 for ; Thu, 26 Mar 2020 18:57:41 +0000 (UTC) (envelope-from bob@proulx.com) Received: from joseki.proulx.com (localhost [127.0.0.1]) by havoc.proulx.com (Postfix) with ESMTP id DB5A95A4 for ; Thu, 26 Mar 2020 12:57:32 -0600 (MDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=proulx.com; s=dkim2048; t=1585249052; bh=onXIDwqcxYk4HexrZOw7kx91Ay4T9FcJ8g91IbWZhoE=; h=Date:From:To:Subject:References:In-Reply-To:From; b=mxy5Zy7XA45OMAy+NVjsgo3Xx0rMq8bGwW+qGTiCfaO7GNJAJjnSc8jwubJ9/ztTM Wcp6QfjHtRN7cj6IKRCUrmwgnWTl/ymDiWADb0DnR7hDQPpbob0Y2+g01cpeMfz4DG QcyAYYqHpzp+Ev7ORTlZig3rKNewHCIEWyZQf6UBCxDddcvHr/8I0WYQPS6Vn5oLUK 6SE4jBBQTatTkFQCy2403uw6Mj+NaxfUjY8et4sndM7G6fT2Gs8BSW0lryVyHwpfHr E9otb3OOSN6C3xfB+796FuJllg07eovoNRo9jFAzmY377WKfx9/sL1Q5qs+bIJoVV1 7Rya95/L5M2HQ== Received: from hysteria.proulx.com (hysteria.proulx.com [192.168.230.119]) by joseki.proulx.com (Postfix) with ESMTP id AD08121152 for ; Thu, 26 Mar 2020 12:57:32 -0600 (MDT) Received: by hysteria.proulx.com (Postfix, from userid 1000) id A3BB82DC93; Thu, 26 Mar 2020 12:57:32 -0600 (MDT) Date: Thu, 26 Mar 2020 12:57:32 -0600 From: Bob Proulx To: freebsd-questions@freebsd.org Subject: Re: drive selection for disk arrays Message-ID: <20200326124648725158537@bob.proulx.com> References: <20200325081814.GK35528@mithril.foucry.net> <713db821-8f69-b41a-75b7-a412a0824c43@holgerdanske.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <713db821-8f69-b41a-75b7-a412a0824c43@holgerdanske.com> X-Rspamd-Queue-Id: 48pDkv36Llz4TM6 X-Spamd-Bar: --- Authentication-Results: mx1.freebsd.org; dkim=pass header.d=proulx.com header.s=dkim2048 header.b=mxy5Zy7X; dmarc=none; spf=pass (mx1.freebsd.org: domain of bob@proulx.com designates 96.88.95.61 as permitted sender) smtp.mailfrom=bob@proulx.com X-Spamd-Result: default: False [-3.03 / 15.00]; ARC_NA(0.00)[]; NEURAL_HAM_MEDIUM(-1.00)[-0.999,0]; R_DKIM_ALLOW(-0.20)[proulx.com:s=dkim2048]; FROM_HAS_DN(0.00)[]; R_SPF_ALLOW(-0.20)[+a]; TO_MATCH_ENVRCPT_ALL(0.00)[]; MIME_GOOD(-0.10)[text/plain]; PREVIOUSLY_DELIVERED(0.00)[freebsd-questions@freebsd.org]; TO_DN_NONE(0.00)[]; RCPT_COUNT_ONE(0.00)[1]; NEURAL_HAM_LONG(-1.00)[-1.000,0]; RCVD_COUNT_THREE(0.00)[3]; DMARC_NA(0.00)[proulx.com]; DKIM_TRACE(0.00)[proulx.com:+]; RCVD_IN_DNSWL_NONE(0.00)[61.95.88.96.list.dnswl.org : 127.0.10.0]; FROM_EQ_ENVFROM(0.00)[]; MIME_TRACE(0.00)[0:+]; RCVD_TLS_LAST(0.00)[]; ASN(0.00)[asn:7922, ipnet:96.64.0.0/11, country:US]; IP_SCORE(-0.53)[ipnet: 96.64.0.0/11(-1.96), asn: 7922(-0.65), country: US(-0.05)] 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 18:57:58 -0000 David Christensen wrote: > Have anyone seen a failure involving multiple similar drives all failing in > the same mode at the same time? For a corporate setting with an SLA and so forth the usual solution is enough drives as hot spares and a fast enough SLA response time to replace drives quickly before too many fail. But even so I have twice seen large corporate arrays with multiple drives failed. They weren't running ZFS though and so didn't detect it until too late. Then they had to restore from backup. Twice now I have had two sibling disks that started out brand new together with relatively close serial numbers in a RAID1 configuration fail within a week of each other. Both times they were in a rack environment in a controlled access room. One was mine and I caught it soon enough with a replacement. One was a client site where they did not and it became a restore from backup task for me. For myself I always buy dissimilar drives to decouple failure modes. If that is not possible then I remix older drives into a set to decouple failure modes. For myself I would rather have one brand new drive with one older drive than two brand new drives. Regardless I always ensure that backup is operating properly. Bob