From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-ID: <3AC10AC8.14A64F76@tnonline.net> Date: Tue, 27 Mar 2001 23:48:56 +0200 From: Anders Widman MIME-Version: 1.0 Subject: Re: [linux-lvm] LVM and fault tolerance References: <3ABA91DE.29985185@tnonline.net> <0103262137020G.01456@lyta> Content-Transfer-Encoding: 7bit Sender: linux-lvm-admin@sistina.com Errors-To: linux-lvm-admin@sistina.com Reply-To: linux-lvm@sistina.com List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: List-Id: Content-Type: text/plain; charset="us-ascii" To: linux-lvm@sistina.com Is it possible to have more than 5 disks in a raid-5 array? Russell Coker wrote: > On Friday 23 March 2001 10:59, Anders Widman wrote: > > > For example, you can create a number of md devices, using RAID1 or RAID5 > > > for fault tolerance, and then run pvcreate on them and manage them with > > > lvm. > > > > > > I'm doing this right now with a 4-disk RAID5 array (3 disks + 1 hot > > > spare), and it seems to be working just fine. > > > > So, how is this actually working then. Let say I have this disk > > configuration: > > > > 2x 40gb > > 2x 60gb > > 2x 80gb > > > > I want maximum amount of diskspace available for storage. High speed is not > > needed at all as this is mainly for storage and streaming low bitrate > > media. Still, I need to be able to add additional disks, maybe two extra > > 80gb disks. Would it be possible to keep ecc/crc data on one disk only, or > > stripe it over all disks. Mirroring is to expensive in this sence too. > > > > The problem with RAID-5 is that all disks need to be of the same size and > > that it is not expandable (or is it?). > > Create a 40G partition on each disk and run RAID-5 over them for 200G of > redundant storage. > Then create a 20G partition on each 60G and 80G disk and make a RAID-5 on > them for 60G of redundant storage. > Then create another 20G partition on each 80G disk and run RAID-1 on them for > 20G of redundant storage. > > That gives 280G of RAID storage. But having 2*RAID-5 and one RAID-1 set on > the same 80G disks won't be good for performance. > > -- > http://www.coker.com.au/bonnie++/ Bonnie++ hard drive benchmark > http://www.coker.com.au/postal/ Postal SMTP/POP benchmark > http://www.coker.com.au/projects.html Projects I am working on > http://www.coker.com.au/~russell/ My home page