From owner-freebsd-fs@FreeBSD.ORG Tue Dec 9 12:41:23 2014 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by hub.freebsd.org (Postfix) with ESMTPS id 2CED69CC for ; Tue, 9 Dec 2014 12:41:23 +0000 (UTC) Received: from mail.ijs.si (mail.ijs.si [IPv6:2001:1470:ff80::25]) (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 D0E3BE5B for ; Tue, 9 Dec 2014 12:41:22 +0000 (UTC) Received: from amavis-proxy-ori.ijs.si (localhost [IPv6:::1]) by mail.ijs.si (Postfix) with ESMTP id 3jxgxC2gdDz16m for ; Tue, 9 Dec 2014 13:41:19 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ijs.si; h= user-agent:message-id:references:in-reply-to:organization :subject:subject:from:from:date:date:content-transfer-encoding :content-type:content-type:mime-version:received:received :received:received; s=jakla4; t=1418128876; x=1420720877; bh=rJy RJCIDLBGWNj4TM/3+jwzU34GAbc/JqcUV6YwNaSU=; b=le/S7cteN3d/9Sy28RT SBwuvlwgzOPRBJSoLQZ4SV2KOoYiRFTJNxbYR4f0pT685o6C7kV6cFI5R8PDGh8M x5vbTheYCNz0gXLG6wi9nL4dx5tWBD/5BH3+yLHJDh7yiXJbxctkkAcwk1QqstND cyhUE8wbqYSAc7SQuJHMx0ak= X-Virus-Scanned: amavisd-new at ijs.si Received: from mail.ijs.si ([IPv6:::1]) by amavis-proxy-ori.ijs.si (mail.ijs.si [IPv6:::1]) (amavisd-new, port 10012) with ESMTP id e4GOfBYc0wQr for ; Tue, 9 Dec 2014 13:41:16 +0100 (CET) Received: from mildred.ijs.si (mailbox.ijs.si [IPv6:2001:1470:ff80::143:1]) by mail.ijs.si (Postfix) with ESMTP for ; Tue, 9 Dec 2014 13:41:15 +0100 (CET) Received: from neli.ijs.si (neli.ijs.si [IPv6:2001:1470:ff80:88:21c:c0ff:feb1:8c91]) by mildred.ijs.si (Postfix) with ESMTP id 3jxgx76MbkzDn for ; Tue, 9 Dec 2014 13:41:15 +0100 (CET) Received: from sleepy.ijs.si ([2001:1470:ff80:e001::1:1]) by neli.ijs.si with HTTP (HTTP/1.1 POST); Tue, 09 Dec 2014 13:41:15 +0100 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: quoted-printable Date: Tue, 09 Dec 2014 13:41:15 +0100 From: Mark Martinec To: freebsd-fs@freebsd.org Subject: Re: ZFS scrub on new disks gives cksum errors Organization: J. Stefan Institute In-Reply-To: <20141209021651.4304976.79605.2556@denninger.net> References: <20141208155230.GA574@iozz.us> <5485CB35.5010608@multiplay.co.uk> <20141209021042.GA649@iozz.us> <20141209021651.4304976.79605.2556@denninger.net> Message-ID: <5216a88b2411cb197af1170e5a81bab0@mailbox.ijs.si> X-Sender: Mark.Martinec+freebsd@ijs.si User-Agent: Roundcube Webmail/1.0.3 X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.18-1 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Tue, 09 Dec 2014 12:41:23 -0000 The key here is 'true on-line' (double-conversion). The waveform itself does not matter much, can be sine or pseudo-sine. Line-interactive and off-line UPS devices with line filters are not good candidates when quality of grid is poor. They handle clean true power outages just fine, but dealing with brownouts and electrical noise calls for a better UPS. Mark 2014-12-09 03:16, Karl Denninger wrote > Stepped-wave ups power is perfectly fine to feed a switching power > supply -- in fact most run COOLER on it than on sine wave power! >=20 > --=C2=A0Karl > From: Brian N > Sent: Monday, December 8, 2014 20:11 > To: Sean Chittenden > Cc: freebsd-fs@freebsd.org > Subject: Re: ZFS scrub on new disks gives cksum errors >=20 > On Mon, Dec 08, 2014 at 09:09:51AM -0800, Sean Chittenden wrote: >> I had this exact problem at home on my FreeNAS host when a box is=20 >> plugged >> in to residential power that is "not clean." If you plug this host in=20 >> to a >> UPS it should clear things up instantly (find a sine wave UPS, not a >> digital stepping supply). There's something about the fluctuating=20 >> power or >> brownouts that ZFS is well suited to detecting (and became terrifying=20 >> to me >> because wtf happened in the past pre-ZFS??). >>=20 >> -sc >=20 > Interesting. I have a UPS (APC Back-UPS ES 550 (stepped)) on the same=20 > circuit > (residential power) that routinely gives me power outage messages where= =20 > an > outage lasts 1-2 seconds. Other electrical devices (lights, etc) are=20 > not > affected and I just thought that the UPS was very sensitive. Thanks for= =20 > the > reply.