From mboxrd@z Thu Jan 1 00:00:00 1970 From: Carlos Mennens Subject: Re: RAID1 On 3 Drives Date: Mon, 15 Mar 2010 07:30:18 -0500 Message-ID: References: <4B9C11FB.7040604@gmx.net> <4B9C24B6.7040507@tmr.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Return-path: In-Reply-To: <4B9C24B6.7040507@tmr.com> Sender: linux-raid-owner@vger.kernel.org To: Mdadm List-Id: linux-raid.ids On Sat, Mar 13, 2010 at 6:50 PM, Bill Davidsen wrote: > Having a spare on raid-1 is fairly pointless, it hurts performance and buys > you nothing. Having one more copy of the data built and ready serves you > better. Can you explain this as I find this interesting. How does having a /boot partition on 3 drives with 1 spare hurt performance? Are you saying that I would get better drive performance if I had all 4 disk partitions active members of my RAID1 /boot? I just don't understand how the 4th disk doing nothing but acting as a spare would hinder performance. Secondly, if the above statement also applies to my / partition? Would you suggest using all 4 drives as active partitions in a RAID5 array too? If I have a 3 disk RAID5 and one hot spare, do you think I would get less performance value for my configuration? Thanks for the clarification!