Re: raid, lvm, and reused disks crashing initramfs

[Bill Davidsen <davidsen@tmr.com>]

Andrew K. Bressen wrote:
> Hi--
>
> I have a linux system running a pair of raid-1 drives, hda and hdc,
> off of the motherboard IDE controller. 
>
> Almost all the space on the disks is in md1. 
> (There's a tiny md0 from an old configuration, the system used
> to boot off of it, but now it's empty and doesn't get mounted).
>
> On top of md1 is lvm, a single PV (horivg) 
> with a bunch of logical volumes in it.
>
> About a year ago, I replaced hda with a newer drive. 
>
> Recently, wanting more disk space, I took the old hda and added
> it back to the machine as hdc. I repartitioned, put lvm on it, 
> creating a sigle PV (hori2vg) with two LVs in it. I copied files
> onto it and such, and all was well. Until a power outage and reboot.
>
> Then, the system crashed into initramfs. Exploring, it became
> evident that initramfs was trying to mount the old disk
> as root. This behavior occurred if the old disk was hdc or hdd. 
>
> Remove the disk, system boots normally.
>
> (Except that X11 no longer works. But I'm just going to choose
> to believe that that's unrelated, even though I didn't change anything,
> and even though that also occurred when the system was hosed a year 
> ago by being booted with hda and hdc reversed.)
>
> The system is an athlon running debian etch; 
> kernel 2.6.22 (debian 2.6.22-3-k7 build).
>
> I'd like to put that disk back in and have my system work. 
>
> Any ideas about what's going on and how to fix it?
>   

You have stale configuration somewhere which causes the drive to be 
mounted. Do you have all of your mdadm mounts using UUID of the 
superblock? Did you zero the superblock(s) on the old drive? At this 
point you might have to zero the whole drive if you're already using 
UUID to start your arrays.

-- 
Bill Davidsen <davidsen@tmr.com>
  "Woe unto the statesman who makes war without a reason that will still
  be valid when the war is over..." Otto von Bismark