From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bill Davidsen Subject: Re: Unsure of changes to array Date: Wed, 17 Oct 2007 16:50:03 -0400 Message-ID: <4716757B.9030609@tmr.com> References: <47161684.7010604@bristol.ac.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <47161684.7010604@bristol.ac.uk> Sender: linux-raid-owner@vger.kernel.org To: Jonathan Gazeley Cc: linux-raid@vger.kernel.org List-Id: linux-raid.ids Jonathan Gazeley wrote: > Dear all, > > This is hopefully a simple question for you to answer, but I am fairly > new to RAID and don't want to risk losing my data! > > My setup is as follows: > - I have four 500GB disks. Each disk is split into a 5GB partition, > and a 495GB partition. > - The four 5GB partitions are in a RAID-5 array, md0. CentOS is > installed on this 15GB partition. > - The four 495GB partiions are in a RAID-5 array, md1. This partition > holds my user data. > > However, I have decided I no longer wish to two arrays across the > disks. I've added a fifth disk on which I have installed the OS > without RAID, meaning the old md0 is currently unused. Can I simply > remove the four 5GB partitions, and resize the four 495GB partitions > to fill the entire disk? Will this break anything? Not unless you make a mistake in typing, or your hardware or power fails during the process. Of course in that case you will possibly lose everything. > > Before anybody tells me off for having the OS on a non-RAID disk, this > is a home server and therefore high availability is not an issue. But > keeping my data safe against disk failures is important to me. Having your o/s and swap on RAID reduces your chances of losing your data. If it were me and reliability were the goal, I would have the o/s mirrored on the first two drives (as seen by the BIOS) so you boot if one fails hard, then put swap RAID-10 in the little 5GB partition on the other three drives, then convert the raid-5 to raid-6 using the rest of the added fifth drive. Anything which reduces the chances of an unclean shutdown improves the chances of keeping your data. A decent UPS is a big help in that regard. Disk failures on the data drives are not the only threat to your data! -- bill davidsen CTO TMR Associates, Inc Doing interesting things with small computers since 1979