From owner-freebsd-fs@FreeBSD.ORG Mon Jun 4 20:53:05 2012 Return-Path: Delivered-To: freebsd-fs@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id C4BA2106566B for ; Mon, 4 Jun 2012 20:53:05 +0000 (UTC) (envelope-from kayasaman@gmail.com) Received: from mail-ee0-f54.google.com (mail-ee0-f54.google.com [74.125.83.54]) by mx1.freebsd.org (Postfix) with ESMTP id 4E7E08FC19 for ; Mon, 4 Jun 2012 20:53:04 +0000 (UTC) Received: by eeke49 with SMTP id e49so1839418eek.13 for ; Mon, 04 Jun 2012 13:53:04 -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:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=Sq9ixjh2NP6fAahixVbG29Utu5VFvnsMFxlJaJcgvzU=; b=j+SBfenxxfDqr4TR6PCt9gjBDQ2pKRIrVILbKlQMqGBHfZYm0Ug/15cK2LxtOL7Eqc ZWr7tWfWt7vfBO3u/tqmhKftV88qs+j98w+TJ9X/yWA5TwbkHupeldWq+IOMg1qLz3bp uUGCTNWGea0u5I8gXWodbY1nB+vdoy+keYA9n6/w2glBA19AGwdum/bgjGTmQddZAygn WBrzhFd8wSXRa97ehbIm+4q1FF+qdM5eWmva1ZF29AFuvaZFNiS/UzW0v4QtKhjbMGxV Fa2xXENZKUeiT/z7lw6N/ZlylUYx3g0SdOpX9ZqoMmVu7QP18pcuM/ueSlSQNYfcsSgc cCGw== Received: by 10.14.22.16 with SMTP id s16mr3208281ees.183.1338843184278; Mon, 04 Jun 2012 13:53:04 -0700 (PDT) Received: from X220.optiplex-networks.com (81-178-2-118.dsl.pipex.com. [81.178.2.118]) by mx.google.com with ESMTPS id e45sm41210300eeb.6.2012.06.04.13.53.02 (version=SSLv3 cipher=OTHER); Mon, 04 Jun 2012 13:53:03 -0700 (PDT) Message-ID: <4FCD202D.2060601@gmail.com> Date: Mon, 04 Jun 2012 21:53:01 +0100 From: Kaya Saman User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:12.0) Gecko/20120430 Thunderbird/12.0.1 MIME-Version: 1.0 To: Johan Hendriks References: <4FCD13CF.3010406@gmail.com> <4FCD17C6.5020503@FreeBSD.org> <4FCD19E6.1010802@gmail.com> <4FCD1F00.5080805@gmail.com> In-Reply-To: <4FCD1F00.5080805@gmail.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-fs@freebsd.org Subject: Re: Using ZFS as RAID0 - disk offline question X-BeenThere: freebsd-fs@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Filesystems List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 04 Jun 2012 20:53:05 -0000 On 06/04/2012 09:48 PM, Johan Hendriks wrote: > Kaya Saman schreef: >> On 06/04/2012 09:17 PM, Matthew Seaman wrote: >>> On 04/06/2012 21:00, Kaya Saman wrote: >>>> in ZFS when using a simple RAID 0 style array is there a way to >>>> recover >>>> a pool after a disk has gone down? >>> No. RAID0 has no resilience to disk failure. That's why things like >>> RAID1, RAID10, RAIDz, RAIDz2 exist: so that your data will survive >>> failure of some number of the drives it is stored on. >>> >>> Make sure you have good backups, basically. >>> >>> Cheers >>> >>> Matthew >>> >> >> Thanks for the responses! >> >> >> I wasn't actually meaning recovering data on the 'downed' disk but on >> the disk that was still online...... >> >> >> You see if say a system board fails and both devices are named >> /dev/ad4 and /dev/ad5 then a new system board gets put in and the >> device names changed to /dev/ad12 and /dev/ad13 my question is will >> the ZPOOL still exist? Will ZFS be intelligent enough to pick up the >> new device names via the disk ID's? >> >> >> Additionally if /dev/ad5 goes down, is it possible to keep using >> /dev/ad4 which is part of the 'downed' pool...?? Or would one need to >> replace the disk ad5 then the pool comes up again with only the >> information on ad4?? >> >> >> This is what I was trying to get at and sorry if I didn't understand >> 100% the direction of the responses! >> >> As in if you meant that the information of on /dev/ad5 will be lost - >> I do understand this :-) >> >> >> Regards, >> >> Kaya >> _______________________________________________ >> freebsd-fs@freebsd.org mailing list >> http://lists.freebsd.org/mailman/listinfo/freebsd-fs >> To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > you can not loose a disk from a raid0 period. > To put it simple, your files are split in half, one part is copied to > disk 1 and the other part on disk2 . > So without the two copies no files, no data. > > If device names changes because of a hardware change, the pool schould > be importable. > But both disks need to be there. > Raid0 should be avoided if possible, better add one disk extra and > create a raidz. > > regards > Johan Hendriks > Yeah, I'm starting to see this now! Of course I don't think it's possible to upgrade from RADI0 to RAIDZ.... Easier to go to RAID1 which gives most protection. Though is not the most efficient method of doing things. Regards, Kaya