From owner-freebsd-questions@FreeBSD.ORG Thu May 23 23:09:27 2013 Return-Path: Delivered-To: freebsd-questions@freebsd.org Received: from mx1.freebsd.org (mx1.FreeBSD.org [8.8.178.115]) by hub.freebsd.org (Postfix) with ESMTP id E579CB8F for ; Thu, 23 May 2013 23:09:27 +0000 (UTC) (envelope-from jrisom@gmail.com) Received: from mail-ie0-x232.google.com (mail-ie0-x232.google.com [IPv6:2607:f8b0:4001:c03::232]) by mx1.freebsd.org (Postfix) with ESMTP id B8F30803 for ; Thu, 23 May 2013 23:09:27 +0000 (UTC) Received: by mail-ie0-f178.google.com with SMTP id f4so2968244iea.37 for ; Thu, 23 May 2013 16:09:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=message-id:date:from:user-agent:mime-version:to:subject:references :in-reply-to:content-type:content-transfer-encoding; bh=i8Nq8D7AFODGAgQ8DKtkESICBc4GiDeqr6iyfacB+T0=; b=0OT3LTxT1rlSJtwKZ+6CjEYH00CTAViJGs0aKw8NpF7wv3lJet5RvJgQ5wBosSF2JN wCLGL/iJQ9pmGvqtcdpRrAouKZptbQnOn0NUKEYcoxx4e6yi8MYKbfZDWtxtmKnqiai5 Mrxmk1Z/KVnYCiF5Uuxjri08hZ8UAqGx/QNhxNfkLG56x8NkNczzSkygm7Pr+opYseIQ 2nFSvtdPn5A9fYk+TMCjr5HquIV49f8+2wd3TIhE26/WxMtUCaFTEMLV9yRloEzsRKZs E/Xj0ZZH26NJrNtHYHiT91BMrCKry5vhmpXPyn8o+YZuMOY8EIBrBSZKc0Lc0eh9++We TiCw== X-Received: by 10.50.80.9 with SMTP id n9mr12144800igx.54.1369350567504; Thu, 23 May 2013 16:09:27 -0700 (PDT) Received: from [192.168.1.34] (c-98-212-197-211.hsd1.il.comcast.net. [98.212.197.211]) by mx.google.com with ESMTPSA id d7sm13995789igx.5.2013.05.23.16.09.26 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 23 May 2013 16:09:26 -0700 (PDT) Message-ID: <519EA18B.8080306@gmail.com> Date: Thu, 23 May 2013 18:08:59 -0500 From: Joshua Isom User-Agent: Mozilla/5.0 (Windows NT 6.2; WOW64; rv:17.0) Gecko/20130328 Thunderbird/17.0.5 MIME-Version: 1.0 To: freebsd-questions@freebsd.org Subject: Re: file corruption solution (soft-update or ZFS) References: In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-BeenThere: freebsd-questions@freebsd.org X-Mailman-Version: 2.1.14 Precedence: list List-Id: User questions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 May 2013 23:09:28 -0000 On 5/23/2013 7:14 AM, saeedeh motlagh wrote: > thanks for your reply. > > you know i have a sensitive server and unfortunately it is located some > where that power outage happens much. so i want guarantee my data and avoid > data lost and file corruption in my server. Get a good reliable UPS. Test it regularly, the batteries do fail. Test to make sure that it will work, unplug it and let the computer drain the battery to time it. Consider that the battery will degrade over time. One thing google does is put a 12V battery inside the chassis to help with the power backup, you might look into it. > i do not have any problem in RAM and hardware. > > i don't know which approach is more suitable for my server. using > soft-update or ZFS. please help me to select the best one. If power failure is an issue, you have no guarantee of data loss protection unless you use networked storage to a safe place. UFS soft updates protects against file system corruption in case of power loss, no guarantees of individual file consistency. ZFS guarantees no silent failures, it doesn't guarantee protection, only that you'll know about it. There is no filesystem that can guarantee you won't lose data in a power failure. Hard drives are known to lie about what's been physically synced to disk out of cache in order to improve speed. If the power goes out at the wrong time, you can lose data. ZFS can find a corrupted file and tell you, everything else won't. If you have a back up of that file, you can restore it. > thank you so much > > > > On Thu, May 23, 2013 at 4:28 PM, Warren Block wrote: > >> On Thu, 23 May 2013, saeedeh motlagh wrote: >> >> hello every body >>> >>> i have a question about fixing file corruption in freebsd. >>> >>> now i have freebsd8.2 and some times file corruption happened on it. this >>> issue has a heavy cost for me and i want to avoid it or fixit it >>> completely. so my question is: >>> >>> is it better to upgrade my freebsd to 9.1 and use soft update or migrate >>> from UFS to ZFS? >>> >> >> That's a judgement call, which means "it depends". >> >> >> i heard so much about soft update -that is added in freebsd9.1- which can >>> fix file corruption in acceptable way with low cost but i don't know how >>> much is reliable and efficient. >>> >> >> Several things: >> >> Soft updates have been around for quite a while. >> Soft updates journaling is the new addition. >> Neither of these address file corruption. Their purpose is to make sure >> the filesystem does not get corrupted, but individual files could still >> contain bad data. >> >> >> in the other hand, i think migration from UFS to ZFS can be another >>> solution. as i read ZFS is is created to solve all the problems related >>> integrity file system. is it reliable enough in comparison soft-update? >>> >>> now, i want to know which solution is better and why? >>> >> >> Again, it depends. Does the target system have enough RAM for ZFS? If >> the file corruption is due to a hardware problem or an application writing >> bad data, no filesystem can prevent that. >> > > >