Re: Grub2 reinstall on raid1 system. Corrections!!!!!
On Mon, 17 Jan 2011 15:50:12 -0600
Jack Schneider <email@example.com> wrote:
> On Mon, 17 Jan 2011 12:48:29 -0700
> Bob Proulx <firstname.lastname@example.org> wrote:
> > Jack Schneider wrote:
> > > Bob Proulx wrote:
> > > > But, and this is an important but, did you previously add the
> > > > new disk array to the LVM volume group on the above array? If
> > > > so then you are not done yet. The LVM volume group won't be
> > > > able to assemble without the new disk. If you did then you
> > > > need to fix up LVM next.
> > >>
> > > NO! I did NOT add /dev/sdb and /dev/sdd to the LVM.. So that is
> > > not a problem.. I was about to do that when the machine failed..
> > Oh good. Then you are good to go. Run these commands to stop the
> > arrays and to reassemble them with the new names.
> > mdadm --stop /dev/md125
> > mdadm --assemble /dev/md0 --update=super-minor /dev/sda1 /dev/sdc1
> > mdadm --stop /dev/126
> > mdadm --assemble /dev/md1 --update=super-minor /dev/sda5 /dev/sdc5
> > Then try rebooting to the system. I think at that point that all
> > should be okay and that it should boot up into the previous system.
> > > Bob, You cannot know how much I appreciate the time and effort
> > > you and others have given to this, hopefully a few more steps and
> > > all will be well..
> > I have my fingers crossed for you that it will all be okay.
> > > I have not done the things you have suggested above. I'll wait
> > > for your response and then go!!!
> > Please go ahead and do the above commands to rename the arrays and
> > to reboot to the previous system. I believe that should work.
> > Hope so. These things can be finicky though.
> > > One other thing I am bothered by, md0, md1 were built using mdadm
> > > v0.90, md2 was built with the current mdadm v 3.1.4. which
> > > changed the md names. Does this matter????
> > Yes. I am a little worried about that problem too. But we were at
> > a good stopping point and I didn't want to get ahead of things. But
> > let's assume that the above renaming of the raid arrays works and
> > you can boot to your system again. Then what should be done about
> > the new disks? Let me talk about the new disks. But hold off
> > working this part of the problem until you have the first part
> > done. Just do one thing at a time.
> > /dev/md127 /dev/sdb /dev/sdd (465G) as yet unformatted
> > ARRAY /dev/md/Speeduke:2 metadata=1.2 name=Speeduke:2
> > UUID=91ae6046:969bad93:92136016:116577fd
> > This was created using newer metadata. I think that is going to be
> > a problem for Lenny/Sqeeze. It says 1.2 but Lenny/Squeeze is
> > 0.90. (A major difference is where the metadata is located. 1.0
> > is in a similar location to 0.90 but 1.1 and 1.2 use locations near
> > the start of the device.) Plus you assigned the entire drive
> > (/dev/sdb) instead of using a partition for it (/dev/sdb1). I
> > personally don't prefer that and always set up using a partition
> > instead of the whole disk.
> > I am not sure the best course of action for the new disks. I
> > suggest stopping the new array, partitioning the drives to a
> > partion instead of the raw disk, then recreating it using the newly
> > created partitions. Do that under your (hopefully now booting)
> > Squeeze system and then you are assured of compatibility. It is
> > perhaps possible that because of the new metadata that the
> > metadata=1.2 array won't be recognized under Squeeze. I don't
> > know. I haven't been in that situation yet. I think that would be
> > good though because it would mean that they would just look like
> > raw disks again without needing to stop the array, if it never got
> > started. Then you could partition and so forth. The future is
> > hard to see here.
> > So that is my advice. If the new array is running then I would stop
> > it. (mdadm --stop /dev/md127) Then partition it, partition /dev/sdb
> > into /dev/sdb1 and /dev/sdd into /dev/sdd1. Then create the array
> > using the new sdb1 and sdd1 partitions. Then decide how to make use
> > of it.
> > Note that if you add new disk to the lvm root volume group then you
> > also need to rebuild the initrd or your system won't be able to
> > assemble the array at boot time and will fail to boot. (Saying that
> > mostly for people who find this in the archive later.)
> > Bob
> Bob, a small glitch. mdadm:/dev/sda1 exists but is not an md array.
> mdadm --stop was successful, before the above.
> It appears that a "--create"-like command is needed. Looks like
> md125 is md0 overwritten somewhere...
> One of the problems of my "no problem found" mentality..
Additionally, maybe I'm in the wrong config. Running from a
sysrescuecd. I do have a current Debian-AMD64-rescue-live cd. Which
I made this AM. I need to find out what's there...
Can I execute the mdadm commands from a "su" out of a busybox prompt?