From mboxrd@z Thu Jan 1 00:00:00 1970 From: Stefan Priebe - Profihost AG Subject: Re: grub2/grub-pc install not possible on mdadm Date: Fri, 02 Mar 2012 14:15:08 +0100 Message-ID: <4F50C7DC.3000700@profihost.ag> References: <4F4C9A11.9060302@profihost.ag> <4F4F4B1D.4050000@redhat.com> <4F4F4EB3.6030909@profihost.ag> <4F4F519E.7040206@redhat.com> <4F508864.4050600@profihost.ag> <20120302100648.fe4e725f2e98880c839357b0@bbaw.de> <4F508EB6.2030101@profihost.ag> <4F5091BF.1000102@anonymous.org.uk> <4F509402.8070503@profihost.ag> <4F50ABA3.1070603@anonymous.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <4F50ABA3.1070603@anonymous.org.uk> Sender: linux-raid-owner@vger.kernel.org To: John Robinson Cc: =?UTF-8?B?TGFycyBUw6R1YmVy?= , linux-raid@vger.kernel.org List-Id: linux-raid.ids > No. When booting with MBR, all that goes in the boot sector is enough to > load the next stage. That next stage will include the raid1x module. It > lives in the gap between the MBR and the first partition - with old > fdisk, that was 31K, with more recent fdisk it's 1MB. With no partition > table on the drives and 1.2 metadata, there's only 3.5K for it, which > isn't enough. But that's why i've a BIOS_GRUB partition on the raid and so also on the disk. Shouldn't it be the same size for 0.9 which starts at the beginning, too? > What's actually happening with metadata 0.90 or 1.0, because they have > their data from the beginning, is that the partition table, GRUB etc > that you have installed into md127 appears to the BIOS as two drives > with boot sectors, partition tables, etc, and it then proceeds to boot > off the first drive. So the bios needs to read the partition table? I thought the MBR would be enough. > Until grub has loaded, you rely on the fact that > what you installed inside the RAID-1 is laid out in exactly the way the > BIOS expects to find it on a single drive. > > What you've done with metadata 1.2 is put GRUB in a place that needs > GRUB to find it. With metadata 0.9 i can install grub on sda and sdb even when there's no part. table. But with 1.2 grub says it cannot find a partition table so it cannot install . So it seems to be a grub bug? grub-probe correctly dectecs a 1.2 metadata md raid on the disks but then still doesn't want to install with the no partition table message. Stefan