From owner-freebsd-fs@freebsd.org Sat Feb 13 17:38:17 2021 Return-Path: Delivered-To: freebsd-fs@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 B2C08533A43 for ; Sat, 13 Feb 2021 17:38:17 +0000 (UTC) (envelope-from bfriesen@simple.dallas.tx.us) Received: from smtp.simplesystems.org (smtp.simplesystems.org [65.66.246.90]) (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 4DdHdj3Yljz4nGd; Sat, 13 Feb 2021 17:38:17 +0000 (UTC) (envelope-from bfriesen@simple.dallas.tx.us) Received: from scrappy.simplesystems.org (scrappy.simplesystems.org [65.66.246.73]) by smtp.simplesystems.org (8.14.4+Sun/8.14.4) with ESMTP id 11DHcA4B001940; Sat, 13 Feb 2021 11:38:10 -0600 (CST) Date: Sat, 13 Feb 2021 11:38:10 -0600 (CST) From: Bob Friesenhahn X-X-Sender: bfriesen@scrappy.simplesystems.org To: Stefan Esser cc: freebsd-fs@freebsd.org Subject: Re: Reading a corrupted file on ZFS In-Reply-To: <225e4da5-79ec-a57a-90e5-35989e6484d5@freebsd.org> Message-ID: References: <0ca45adf-8f60-a4c3-6264-6122444a3ffd@denninger.net> <899c6b4f-2368-7ec2-4dfe-fa09fab35447@artem.ru> <20210212165216.2f613482@fabiankeil.de> <10977ffc-f806-69dd-0cef-d4fd4fc5f649@artem.ru> <2f82f113-9ca1-99a9-a433-89e3ae5edcbe@denninger.net> <2bf4f69c-9d5d-5ff9-0daa-c87515437ca3@artem.ru> <5aa03138-1dc8-5a9c-1be6-d47ed22fc0cf@denninger.net> <225e4da5-79ec-a57a-90e5-35989e6484d5@freebsd.org> User-Agent: Alpine 2.20 (GSO 67 2015-01-07) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (smtp.simplesystems.org [65.66.246.90]); Sat, 13 Feb 2021 11:38:10 -0600 (CST) X-Rspamd-Queue-Id: 4DdHdj3Yljz4nGd X-Spamd-Bar: ---- Authentication-Results: mx1.freebsd.org; none X-Spamd-Result: default: False [-4.00 / 15.00]; REPLY(-4.00)[] X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Sat, 13 Feb 2021 17:38:17 -0000 On Sat, 13 Feb 2021, Stefan Esser wrote: > > I have a number of older 2 TB drives and use 2 of them to store > DVB transport stream data, for later processing. They are not > mirrored and the data format assumes that the transmission is not > perfect. I have noticed that some of these files have been lost > due to bad sectors, and while this would not be a problem on UFS, > ZFS thinks I should not trust the file at all, despite 99,9999% > of it being perfectly usable. (A fraction of the TS data is > extracted from these files and stored as PS data on a ZFS RAID, > where it will be safe and I never lost a file.) If simple bad sectors is a problem for you on zfs, then try setting the the filesystem 'copies' property to a value higher than one before writing the file. This does use more space but does not require additional devices. Bob -- Bob Friesenhahn bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer, http://www.GraphicsMagick.org/ Public Key, http://www.simplesystems.org/users/bfriesen/public-key.txt