From mboxrd@z Thu Jan 1 00:00:00 1970 From: jim owens Subject: Re: Converting system to raid Date: Sat, 11 Apr 2009 11:04:40 -0400 Message-ID: <49E0B188.8050009@hp.com> References: <003801c9b96d$21a0f420$0a00a8c0@vorg> <49DF0D06.8030705@musmo.com> <20090410195303.GB21242@cthulhu.home.robinhill.me.uk> <00cc01c9ba1d$3aefecf0$0a00a8c0@vorg> <20090410205942.GC21242@cthulhu.home.robinhill.me.uk> <00f301c9ba23$032025f0$0a00a8c0@vorg> <20090410215129.GD21242@cthulhu.home.robinhill.me.uk> <019701c9ba66$aeed5630$0a00a8c0@vorg> <20090411143642.GA9915@cthulhu.home.robinhill.me.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20090411143642.GA9915@cthulhu.home.robinhill.me.uk> Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids Robin Hill wrote: >> From: "CoolCold" >> >> # rsync -avHhx --progress --delete / /mnt/raid-md0 >> > Yes, this is an alternative to running from a bootable CD. In > single-user mode (init 1), there can be no background applications > running, so there should be no open files to worry about. I'd still > rather use a bootable CD though. Strong ACK on bootable CD as the right method, or doing it all while init 1... not as a 2-step multi-user mode, single user. rsync is a very good tool but unless you use: -c, --checksum skip based on checksum, not mod-time & size the consistency between runs is not 100% safe. It may be 99.9%, but the problem is that for file blocks being rewritten you don't know what is on disk or in memory and mod-time only changes at the whim of the FS (I'm an FS developer) and at the granularity of the FS and system clock... nanosecond time stamps are a myth! And if you are going to use the rsync -c 2-pass method it will probably take your system off line longer than a CD boot and copy. At the end of process, is 99.9% good enough? For much of my backup needs it is because I only care about not loosing more than a small amount of work. But if I'm converting to a new disk and loosing the old one, I want 100%. jim