From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <3FE66033.6070109@alteeve.com> From: Madison Kelly MIME-Version: 1.0 Subject: Re: [linux-lvm] Ext3 -> ReiserFS on '/' conversion problem References: <20031220005645.GA7068@mail.parplies.de> In-Reply-To: <20031220005645.GA7068@mail.parplies.de> 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: Date: Sun Dec 21 21:10:02 2003 List-Id: Content-Type: text/plain; charset="us-ascii"; format="flowed" To: linux-lvm@sistina.com Thank you for such a lengthy responce, Holger. While I backup '/' to '/etc/sdd1' I have '/dev/sdd1' formatted as 'ext3'. I will try making custom kernel in the morning to be sure that ReiserFS is natively supported. I guess the biggest question in that last post I had was how can I force the OS to use the '/etc/sdd1' as the root partition instead of '/dev/vg0/root'? It isn't directly an LVM question though so I may have stepped out of bounds asking that one here... The joys of being new. As for extending the RAID array, I feared that what you said may be true. I am trying to build a storage platform that can (after going live) survive a disk failure and have space added without taking the partition off-line. I've read about the raid tools and I hoped that once I extended the RAID5 array (assuming I can do so, one disk at a time) I then wanted to pass the new space along to LVM... Am I attempting the impossible? :p Thank you again, everyone here is so helpful! Madison wopp@parplies.de wrote: > Hi, > > at some point in this thread, Madison Kelly wrote: > >>I am still getting a kernel panic now but it no longer >>seems to have anything to do with LVM, simply it is -still- looking for >>an ext3 partition and obviously failing to find it. > > > sorry to say so, but it never did have anything to do with LVM. Unless I > completely misunderstood you, you first had / on LVM as ext3, and it worked. > When you try to boot with / on /dev/sdd1 as reiserfs, it doesn't work. > > It may sound obvious (and the thread has already come to this conclusion - > I'm just trying to make it more clear), but your kernel doesn't support > reiserfs, so you have to load reiserfs as a module from initrd - by whatever > means Redhat provides or by manually creating an appropriate initrd (if you > do that, use the one you have as a starting point). Or, of course, compile a > kernel with reiserfs support built in. > > You don't need to do any of this from the 'rescue disk' (especially not > compile a kernel ;-). You can just as well boot into your normal setup (with > / as ext3). If I'm not totally mistaken, the FS type of / is not specified > anywhere but rather autodetected by the kernel on boot. Between booting into > your ext3 system on /dev/vg0/root and your reiserfs copy on /dev/sdd1, you > don't have to change any files. Come to think of it, how would the kernel > use any file-based information to determine the type of the root FS? It would > obviously need to mount / before reading the configuration, so once it can > read it, it doesn't need it any more. > And you can most probably tell GRUB what root device it is to pass to the > kernel on its boot command line too [I don't use GRUB, so I can't tell you > how] - or specify two alternative boot targets in the configuration file. > > Concerning the 'df' output, 'df' takes its information from /etc/mtab, so if > you put the line > > /dev/ttyS0 / ext3 rw 0 0 > > in there, it may appear as though your first serial port were mounted on > / :-). Nothing really seems to need to know where / physically resides, or > if they do (LILO ...), they have better means of finding out [though I've > never tried running 'lilo' with /boot as a part of / and the above entry in > /etc/mtab :-]. This seems to result in not much effort being put into > writing the correct root device name into /etc/mtab on boot (see the > 'rootfs' output of 'df' on your 'rescue disk' - that simply means 'well, > whatever it may be'). > > It IS sometimes confusing when you want to be 100% sure which disk you are > operating on. It might help to go by the size reported by 'df', which should > be accurate in any case. > > >>Anyway, I am off to try converting again now that I know to try passing >>"init=reiserfs" in grub (will it work though?... Off to see!) > > > What would that do? Run 'reiserfs' [relative to the CWD, probably /] instead > of /sbin/init after mounting the root FS? ;-) > > > A remark on your original question: > >>Am I on the right track? > > > I don't think you'll be able to resize a software raid array and extend the > PV. Can you create your array in degraded mode instead (with three data disks > and the fourth one marked 'failed')? Then you'd have your spare disk for > installation which you could later 'raidhotadd' to the array to get your > parity information rebuilt. I don't think you're too worried about > interruption of service during the installation ;-). > I doubt a standard installation frontend supports this though, so you might > need a bit of tweaking to get that to work. > > Hope that helps in some way. > > Holger