From mboxrd@z Thu Jan 1 00:00:00 1970 From: Phillip Susi Subject: Re: - info about dm Date: Mon, 12 Nov 2007 16:15:56 -0500 Message-ID: <4738C28C.1090300@cfl.rr.com> References: <00c401c82145$5a337180$27819296@wegaprise> <20071109163746.GB15775@percy.comedia.it> Reply-To: device-mapper development Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: quoted-printable Return-path: In-Reply-To: <20071109163746.GB15775@percy.comedia.it> 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, ataraid-list@redhat.com List-Id: dm-devel.ids Luca Berra wrote: >> Anyway, I found a little problematic configuring it manually: I tried = to >> install SL5 on a node which was misconfigured: instead of seeing one >> device, it was managing the 2 HD (/dev/sda and /dev/sdb) as 2 separate This is as expected. The hardware is just a sata controller with two=20 disks attached, so that is what the kernel sees. dmraid is used to=20 recognize the bios information on the disk and configure the device=20 mapper driver to create a raid virtual device. >> devices an if I tried to configure them (at install time, via CD or >> network boot) with DM, I got many errors about the RAID table (=93ERR= OR: >> asr: Invalid RAID config table checksum on /dev/sda=94 or even =93asr: >> Invalid magic number in RAID table; saw 0x0 expected=85=94). I tried t= o >> reconfigure the RAID card first via BIOS and then trying again to >> configure it via Linux (=93dmsetup create =85=94) but even if it seeme= d dmsetup create creates a new dm device. Generally this command is for=20 debugging and testing, so you should not use it. It has nothing to do=20 with dmraid other than they are both clients of the device mapper kernel=20 driver. >> working (exit code 0), then querying the device asr_ (i.e. =93dmraid =96= r=94) >> resulted in errors as reported above=85or better, dmraid commands (-r, >> -ay, -tay,=85) reported errors, while dmsetup commands (status, ls,=85= ) What where the exact commands and errors the generated? I am also confused because the first thing you said was that the system=20 DID correctly recognize the raid array as /dev/mapper/asr_xxxx. >> 2) Managing disks >> I configured disks in RAID 1 (mirror) but I wonder how to manage this >> RAID; in particular, how can I do for: >> - stopping a device (disk) and put it offline/and viceversa? -=20 >> reconfiguring/rebuilding it (due to broken/faulting HD)? >> At the moment I should change a couple of disks (SMARTD warnings >> reported), but I=92m scared about the =93RAID table error=94=85 Currently the only way is to do so in the bios. Some systems the bios=20 will begin rebuilding when you tell it to, and you need to wait for it=20 to finish. On others, it only marks the disk as needing rebuilt and=20 relies on the windows driver to do the rebuilding. Currently dmraid=20 does not perform rebuilding.