Re: Grub2 reinstall on raid1 system. Corrections!!!!!
On Mon, 17 Jan 2011 12:48:29 -0700
Bob Proulx <bob@proulx.com> 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..
Jack
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