From owner-freebsd-fs@freebsd.org Mon Nov 9 20:55:14 2015 Return-Path: Delivered-To: freebsd-fs@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2AFBFA29782 for ; Mon, 9 Nov 2015 20:55:14 +0000 (UTC) (envelope-from steven@multiplay.co.uk) Received: from mail-wm0-x236.google.com (mail-wm0-x236.google.com [IPv6:2a00:1450:400c:c09::236]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client CN "smtp.gmail.com", Issuer "Google Internet Authority G2" (verified OK)) by mx1.freebsd.org (Postfix) with ESMTPS id BD2FF132F for ; Mon, 9 Nov 2015 20:55:13 +0000 (UTC) (envelope-from steven@multiplay.co.uk) Received: by wmww144 with SMTP id w144so92709400wmw.1 for ; Mon, 09 Nov 2015 12:55:11 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=multiplay_co_uk.20150623.gappssmtp.com; s=20150623; h=from:mime-version:references:in-reply-to:date:message-id:subject:to :cc:content-type; bh=2eOc4z3CuXumacNpojNxycxU2iUxjQwZ5fzi51ocYdU=; b=MZmti1RvKgiri3stBS77vbc8Viunwd7dYNjClMYitd9jEFtUm6NOYvd8OfKGka6eVL 2ZReuDAiA4ozlJG2YIUHdzlbmbsayXftSHlu3kA7MiMSRibrTbgiPiQ2/jFGci+gk8gb iyL+1l2owcBYN5gjyKrIjkkd6GMeVmkhoXSKBsVt6mqODlK+sW2sMI+Vyl0UeVlMA1vi a+aSMr0yWRJ0W2wJpjTv0f6c1QPpj8TpWepzv9rvoFWUMRPBlYBrfllU1wvg0ljRporn 74c4fI8xSsBlTzAvZ6InLz2ECvTWaqvliKa/QTbuRfG84aKWaKgfCRvUsGfSNlSeZJEE RMhw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:mime-version:references:in-reply-to:date :message-id:subject:to:cc:content-type; bh=2eOc4z3CuXumacNpojNxycxU2iUxjQwZ5fzi51ocYdU=; b=duRqu5LXKqrkao1RZxMt1JmOItmYuSe3M6+wsdp8u1LHZ0hdmeWbXOvEhk7qfptYUi 4HyXDOmQI9/m2cQXbnY5/FsMYpKuvA7j8gb+z5OFq5AJNuW3u6xDOqsW8JiMptVVG82Y bHgLrJVM5OoPqE2G1KebK8J1lQNS0tTacVhCq1L9oWcSzbyGd5+hYabjdUqMedeu8DJZ iITglA6CAD1dmYyQ8ktG/JqtLQZa6fkiLA9yFDGKFx+SDEJvQRqbJH15Y5EOgQhKwFmo zKJcgO6pHCEEVbmwpLqVoETlmBdaiS8M0lgOkhr8ppXX1e8QxAR3mh34QHRI3csezstw Mx4g== X-Gm-Message-State: ALoCoQmHof+fSyOzFAFfYZLhknyqWvFhDEGJdPN60L4MV+K5+S9FPsAOCUTZbwvcpHz+sBOg5VDy X-Received: by 10.194.123.162 with SMTP id mb2mr36896179wjb.32.1447102511802; Mon, 09 Nov 2015 12:55:11 -0800 (PST) From: Steven Hartland Mime-Version: 1.0 (1.0) References: In-Reply-To: Date: Mon, 9 Nov 2015 20:55:11 +0000 Message-ID: <-7786625913476013857@unknownmsgid> Subject: Re: ZFS RAID 0+1 Throwing Checksum Errors To: Tim Gustafson Cc: "freebsd-fs@freebsd.org" Content-Type: text/plain; charset=UTF-8 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.20 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 09 Nov 2015 20:55:14 -0000 I would check for bad memory or cabling. If you have a hot swap midplane and the disks are linked at 6gbps that could also be the issue. In short it's more likely to be a hardware issue than software > On 9 Nov 2015, at 19:09, Tim Gustafson wrote: > > I have a FreeBSD 10.1 server configured as root-on-zfs with the > following pool configuration: > > NAME STATE READ WRITE CKSUM > tank ONLINE 0 0 0 > mirror-0 ONLINE 0 0 0 > gpt/zfs0 ONLINE 0 0 0 > gpt/zfs1 ONLINE 0 0 0 > mirror-1 ONLINE 0 0 0 > gpt/zfs2 ONLINE 0 0 0 > gpt/zfs3 ONLINE 0 0 0 > > The disks are each 1TB Samsung 850EVO SSDs connected via an mrsas Dell > Perc raid controller configured in "RAID Disabled" mode. > > I run a "zpool scrub" every weekend and every weekend the scrub finds > a handful (usually between 1 and 10) checksum errors per disk. The > scrub fixes the checksum errors, and I clear the counters and > everything seems fine. As far as I know, I do not have any corrupt or > missing data. > > The server is a fairly busy web and database server, handling about 5 > million hits per day. > > I'm wondering if the problem is that the scrub is calculating the > checksum for the data on gpt/zfs0, and while that's happening, some > data is updated by Apache or MySQL, and then checksum for the data on > gpt/zfs1 is calculated, which now doesn't match, and therefore the > scrub is reporting an error. Is that possible? > > If that's not it, could this be a bug? Or should I be worried about > my SSDs? What additional data would be helpful for me to share to > diagnose this? > > -- > > Tim Gustafson > Technical Lead, Baskin School of Engineering > tjg@ucsc.edu > 831-459-5354 > Baskin Engineering, Room 313A > _______________________________________________ > freebsd-fs@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org"