On Mon, Nov 19, 2012 at 8:39 AM, Phil Turmel <philip@xxxxxxxxxx> wrote: > Hi Drew, > > On 11/18/2012 02:10 PM, Drew Reusser wrote: > > [trim /] > >> Sorry - did not know the rules about top posting. Is there something >> specific in the dmesg you are looking for? I tried to mount it again >> and copied everything in the buffer. > > Here's what I wanted to see: > >> [270303.640240] EXT4-fs (md0): VFS: Can't find ext4 filesystem > > This suggests that the ext4 superblock isn't near the beginning like > it's supposed to be. One of the ways that happens with MD raid is if > someone does "mdadm --create" and destroys their old raid superblocks. > > I went back and looked at: > >> Creation Time : Thu Nov 15 16:08:02 2012 > > and: > >> Data Offset : 262144 sectors > > So you've re-created the MD array. That's bad. Chunk size and Data > offset size and alignment defaults have changed in the past couple > years, so re-creating an array with a different mdadm version can cause > these problems. You can also lose the original order of devices, with > similar consequences. > > (Side note: there's various pieces of advice floating around the > internet on recovering a broken array that start with re-creating the > array. It's horribly wrong, and only a last resort, and only after > recording all the details about the original array.) > > Unless you kept a copy of "mdadm --examine /dev/sd[abde]1" for the > original array, this will be difficult to debug further. Your best > chance is to go back to the version of mdadm available when you first > built the system and recreate with that, trying the various device order > combinations. > > Don't attempt to mount to check for success. First, use "fsck -n" to > non-destructively check the FS. If that gives few errors, then you can > mount the FS. > > Phil Looking at this from all angles, is there a way to look at the individual disks (like sdb and sde) and build a raid 0 from them and see if that works? Is there a way to see which if any are bad from a file system point of view and exclude it and try to rebuild it? I am just grasping at straws trying to figure out which way to go. -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
