From mboxrd@z Thu Jan 1 00:00:00 1970 From: Giovanni Tessore Subject: Re: Linux mdadm superblock question. Date: Sat, 13 Feb 2010 09:37:00 +0100 Message-ID: <4B7664AC.4080504@texsoft.it> References: Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-raid-owner@vger.kernel.org To: linux-raid@vger.kernel.org List-Id: linux-raid.ids > I may be converting a host to ext4 and was curious, is 0.90 still the > only superblock version for mdadm/raid-1 that you can boot from > without having to create an initrd/etc? > > Are there any benefits to using a superblock > 0.90 for a raid-1 boot > volume < 2TB? I recently reinstalled my systems, and I had to use superblock 0.9 to be able to boot ext4 from raid-1 (kernel 2.6.31 - grub2 1.97-beta4). I didn't go deep with it as I was quite in hurry, so I'm not sure if it depends by grub2 or by kernel's md autodetection at boot. I used superblock 1.1 for the others md devices. The advantage of superblocks >= 1.0 that I prefere is that they persist the number of recovered read errors; this allow to monitor (at the moment manually via /sys/block/mdXX/devYY/errors) across system restarts the health of devices into the array, useful for raid-5 and 2-disks raid-1. Regards -- Cordiali saluti. Yours faithfully. Giovanni Tessore