From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mx1.redhat.com (mx1.redhat.com [172.16.48.31]) by int-mx1.corp.redhat.com (8.11.6/8.11.6) with ESMTP id j2V7cJO16642 for ; Thu, 31 Mar 2005 02:38:19 -0500 Received: from percy.comedia.it (percy.comedia.it [212.97.59.71]) by mx1.redhat.com (8.12.11/8.12.11) with ESMTP id j2V7cIqs004922 for ; Thu, 31 Mar 2005 02:38:19 -0500 Date: Thu, 31 Mar 2005 09:38:17 +0200 From: Luca Berra Subject: Re: [linux-lvm] Re: putting lvm autodetect into the kernel ala md Message-ID: <20050331073816.GD3879@percy.comedia.it> References: <20050330065236.GA18365@percy.comedia.it> Mime-Version: 1.0 Content-Disposition: inline In-Reply-To: Reply-To: LVM general discussion and development List-Id: LVM general discussion and development List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" Content-Transfer-Encoding: 7bit To: LVM general discussion and development On Wed, Mar 30, 2005 at 11:38:16PM +0800, Andy Sy wrote: >Luca Berra wrote: > >> >Just like the kernel is now able to autodetect and >> >autoenable md RAID arrays, are there plans to make > >> kernel autodetection of md arrays is almost always a >> bad idea, it is far better to use mdadm in user space for that. > >Why is this necessarily so? RAID autodetect seems to >avoid a lot of configuration hassles especially when your >root partition is involved. Any horror stories to tell? yes, read the linux-raid mailing list for those, i am tired of beating the same dead horse. >> >lvm do the same? (i.e integrate the functionality >> >of vgscan / vgchange -ay,-an into the kernel) > >> no, it is an user space task, there is no reason to >> burden the kernel with this. > >People have recommended against using an LVM >volume for your root partition citing the hassle of >a rescue disk as being the main reason. If lvm volume this is just ridicolous fud. in what cases you would need a rescue disk? are those really different from the cases you'd need a rescue disk for a normal partition-table based system. besides, every live distro on earth now supports lvm and can be used as a recovery tool. >autodetect and enabling were in the kernel, then >this would no longer be the case. why? >I have a good reason for wanting my root partition >to be a logical volume: this is because I can i have been using my root partition as a logical volume for several years now. >Unless lvm detect/enable functionality were built into >the kernel though, you will always have to live with a >physical partition holding /boot - the case today >with LVM and RAID0, but not RAID1 (from which it is >possible to boot directly off of). i don't have a separate partition for /boot on my lvm systems. the only reason i needed a separate boot partition was when i had a system using raid5, so i had to have a separate raid1 partition for booting. Reading your arguments it appeare you are mis-informed and make a lot of confusion between a boot loader (which is the only limitation we have in loading a kernel/initrd/initramfs) and what the kernel can do. Regards, Luca -- Luca Berra -- bluca@comedia.it Communication Media & Services S.r.l. /"\ \ / ASCII RIBBON CAMPAIGN X AGAINST HTML MAIL / \