From mboxrd@z Thu Jan 1 00:00:00 1970 From: tormen Subject: Questions about dm-raid isw (device naming and partition table) Date: Fri, 06 Aug 2010 11:42:41 -0400 Message-ID: <4C5C2D71.7010706@gmx.net> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dm-devel-bounces@redhat.com Errors-To: dm-devel-bounces@redhat.com To: dm-devel@redhat.com List-Id: dm-devel.ids Hi everybody, I am new to dm-raid and have a couple of questions regarding how it works (specifically regarding the device naming and access to the partition table). Any answer (or references to documentation) would be great! Before I start with my questions: A short description of my use case for dm-raid isw: I am having a notebook with a RAID-0 (stripe) intel fake hardware raid (on 4 sata devices :)). Out of the box (setup by the manufacturer - with Win7) when starting with the linux rescue cd (that used dm-raid isw), I got these partitions: dm-0 (seemed to be everything == the 4 drives combined) dm-1 (primary partition) dm-2 (primary partition, active) dm-3 (primary parition) After repartioning (with linux based acronis disk-director that also uses dm-raid isw) now I have: dm-0, dm-1, ... dm-10 where dm-0 still seems to be the WHOLE raid-disk and dm-1 to dm-10 represent the 10 partitions (logical and/or primary). ////////////////////////////////////////////////////////////////////////////////////////////////////////////// /1st/ question: With dm-raid isw and 1 RAID: dm-0 is everything (like the whole virtual (raid) disk)? /2nd/ question: Can I use cfdisk to access the parition table / view the partioning under linux? ... because when I try cfdisk /dev/dm-0 I get this error message: "FATAL ERROR: Bad primary partition 1: Partition ends in the final partial cyllinder And the same when I try to print the partition table with cfdisk. If I start cfdisk -z /dev/dm-0 it works and could (from scratch) partition the raid-drive. But I noticed that then the partitions seem to be called dm-0p1, dm-0p2 (I hope I recall the naming correctly). /3rd/ question: Why would the partitions be called dm-0p1, dm0p2, ... within cfdisk while otherwise I see dm-1, dm-2, ... ? What is the difference between dm-0p1 and dm-1? /4th/ question: So regardless of logical / primary partitions the devices are always named consecutively (1, 2, 3...)? (in contrast to: /dev/sda1.../dev/sda4 beging primary paritions and /dev/sda5 being the first logical partition) /5th/ question: Is there a way to partition the raid (e.g. with cfdisk) under linux (without using third party software like acronis) so that Win7 and Linux can access the raid-drive / partition table ((and don't complain about fatal errors))? /6th/ question: Does the "partition 1" from the above cfdisk fatal error message refer to /dev/dm-1 (because that is the 1st partition on the raid device /dev/dm-0) or what partition / device does it refer to? Thanks a lot in advance for any hint / advise! Best, Knuth