I'd like to rename my existing volume groups and logical volumes (I picked names a long time ago I no longer like :-). I recently stumbled across the lvrename and vgrename commands, but when I tried the former to rename the logical volume that my root partition resides on, the system became unbootable.
In addition to renaming the LV (and VG if I decide to to that as well), what else needs to be changed? So far my list includes:
o /etc/fstabb o /boot/grub/grub.conf o /dev/<vgname>/<lvnamex> o /dev/mapper/<vgname-lvnamex>
I was hoping the lvrename and/or vgrename would take care of these details. Are there any scripts out there that take care of all the details? If not, I may write one (once I have the recipe to get this working, of course).
Alfred
I have never done this before, but I would think that the only thing that you would have to change would be fstab and your grub configuration. vgrename and lvrename did not recreate items under /dev?
Did you get the system booting or is this more of just a list for a script that you are planning to create?
Josh Gimer
On May 2, 2008, at 3:04 PM, Alfred von Campe wrote:
I'd like to rename my existing volume groups and logical volumes (I picked names a long time ago I no longer like :-). I recently stumbled across the lvrename and vgrename commands, but when I tried the former to rename the logical volume that my root partition resides on, the system became unbootable.
In addition to renaming the LV (and VG if I decide to to that as well), what else needs to be changed? So far my list includes:
o /etc/fstabb o /boot/grub/grub.conf o /dev/<vgname>/<lvnamex> o /dev/mapper/<vgname-lvnamex>
I was hoping the lvrename and/or vgrename would take care of these details. Are there any scripts out there that take care of all the details? If not, I may write one (once I have the recipe to get this working, of course).
Alfred
CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
On Fri, 2008-05-02 at 17:04 -0400, Alfred von Campe wrote:
I'd like to rename my existing volume groups and logical volumes (I picked names a long time ago I no longer like :-). I recently stumbled across the lvrename and vgrename commands, but when I tried the former to rename the logical volume that my root partition resides on, the system became unbootable.
In addition to renaming the LV (and VG if I decide to to that as well), what else needs to be changed? So far my list includes:
o /etc/fstabb o /boot/grub/grub.conf o /dev/<vgname>/<lvnamex> o /dev/mapper/<vgname-lvnamex>
I was hoping the lvrename and/or vgrename would take care of these details. Are there any scripts out there that take care of all the details? If not, I may write one (once I have the recipe to get this working, of course).
Remake your initrd. In there is a reference to the volgroup/lvol that you will want to change. Or you can add and change the parameter to ignore check failures.
Then just the usual fstab, local scripts, etc.
Alfred
<snip sig stuff>
HTH
Alfred von Campe wrote:
I'd like to rename my existing volume groups and logical volumes (I picked names a long time ago I no longer like :-). I recently stumbled across the lvrename and vgrename commands, but when I tried the former to rename the logical volume that my root partition resides on, the system became unbootable.
In addition to renaming the LV (and VG if I decide to to that as well), what else needs to be changed? So far my list includes:
o /etc/fstabb o /boot/grub/grub.conf o /dev/<vgname>/<lvnamex> o /dev/mapper/<vgname-lvnamex>
I was hoping the lvrename and/or vgrename would take care of these details. Are there any scripts out there that take care of all the details? If not, I may write one (once I have the recipe to get this working, of course).
Sure you can do all this from rescue mode off the first CD.
Boot the cd type in 'linux rescue' and continue to the command prompt.
At the command prompt:
1) make sure swap isn't using the swap lv - swapoff -a
2) unmount all lvs mounted - umount /mnt/sysimage/boot - umount /mnt/sysimage
3) mark all lvs as unavailable - lvchange -a n <vgname>
4) rename the volume group - vgrename <oldvgname> <newvgname>
5) rename the logical volumes - lvrename <vgname><oldlvname> <newlvname>
6) repeat #5 as necessary
7) re-activate all the lvs - lvchange -a y <vgname>
8) re-mount the root and boot lvs, - mount /dev/<vgname>/<rootlv> /mnt/sysimage - mount /dev/<vgname>/<bootlv> /mnt/sysimage/boot
9) chroot to the mounts with, 'chroot /mnt/sysimage /bin/bash'
10) edit /etc/fstab
11) edit /boot/grub/grub.conf
That should do it.
-Ross
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Ross S. W. Walker wrote:
Alfred von Campe wrote:
I'd like to rename my existing volume groups and logical volumes (I picked names a long time ago I no longer like :-). I recently stumbled across the lvrename and vgrename commands, but when I tried the former to rename the logical volume that my root partition resides on, the system became unbootable.
In addition to renaming the LV (and VG if I decide to to that as well), what else needs to be changed? So far my list includes:
o /etc/fstabb o /boot/grub/grub.conf o /dev/<vgname>/<lvnamex> o /dev/mapper/<vgname-lvnamex>
I was hoping the lvrename and/or vgrename would take care of these details. Are there any scripts out there that take care of all the details? If not, I may write one (once I have the recipe to get this working, of course).
Sure you can do all this from rescue mode off the first CD.
Boot the cd type in 'linux rescue' and continue to the command prompt.
At the command prompt:
make sure swap isn't using the swap lv
- swapoff -a
unmount all lvs mounted
- umount /mnt/sysimage/boot
- umount /mnt/sysimage
mark all lvs as unavailable
- lvchange -a n <vgname>
rename the volume group
- vgrename <oldvgname> <newvgname>
rename the logical volumes
- lvrename <vgname><oldlvname> <newlvname>
repeat #5 as necessary
re-activate all the lvs
- lvchange -a y <vgname>
re-mount the root and boot lvs,
- mount /dev/<vgname>/<rootlv> /mnt/sysimage
- mount /dev/<vgname>/<bootlv> /mnt/sysimage/boot
chroot to the mounts with, 'chroot /mnt/sysimage /bin/bash'
edit /etc/fstab
edit /boot/grub/grub.conf
That should do it.
Oh, I forgot, as Bill pointed out...
12) remake the initrd - mkinitrd -f /boot/initrd-$(uname -r).img $(uname -r)
Does uname work correctly chroot'd? I'll have to test that out...
-Ross
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On Fri, 2008-05-02 at 17:28 -0400, Ross S. W. Walker wrote:
Ross S. W. Walker wrote:
Alfred von Campe wrote:
<snip>
Oh, I forgot, as Bill pointed out...
- remake the initrd
- mkinitrd -f /boot/initrd-$(uname -r).img $(uname -r)
In the output from the gzip -dc <initrdfile> | cpio -idumv is a file named init. Look around this area.
echo Creating root device. mkrootdev -t ext3 -o defaults,ro /dev/VolGroup00/LogVol00 echo Mounting root filesystem.
<snip>
Josh, Bill, and Ross, than you for all the suggestions. I'm running out of time to try them today, but I will do so on Monday when I'm back in the office and I"ll post an update.
TGIF! Alfred
Alfred von Campe wrote:
Josh, Bill, and Ross, than you for all the suggestions. I'm running out of time to try them today, but I will do so on Monday when I'm back in the office and I"ll post an update.
Sounds good, I verified uname doesn't work under rescue and there are a couple other problems with /proc /sys being mounted under /mnt/sysimage. I have done it successfully with the FC8 cd though.
-Ross
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On May 2, 2008, at 17:24, Ross S. W. Walker wrote:
Sure you can do all this from rescue mode off the first CD.
Boot the cd type in 'linux rescue' and continue to the command prompt.
First, thanks for the detailed list, Ross. It was very helpful. I was able to rename both the VG and the LVs, but it was slightly more complicated than the items on the list.
- make sure swap isn't using the swap lv
- swapoff -a
What I did was say "Skip" when the rescue image asks you if you want it to find existing Linux installations and mount them under /mnt/ sysimage. The reason I did this was that if you let it mount your partitions, you need to go through a lot of additional steps to get everything under /mnt/sysimage unmounted, and nothing in there is needed to do the rename (unless you want to rename the VG -- see below).
- unmount all lvs mounted
- umount /mnt/sysimage/boot
- umount /mnt/sysimage
Not needed because of what I did in step 1, but there are additional mount points to unmount if you do let the rescue image do the mounts (do a "mount | grep sysimage" to find all the mount points).
- mark all lvs as unavailable
- lvchange -a n <vgname>
This step is indeed required unless you chose to skip the mounting of /mnt/sysimage altogether. Do a "lvm lvscan" to find out which LVs are active (and use "lvm lvchange" as described below).
- rename the volume group
- vgrename <oldvgname> <newvgname>
Well, vgrename is not part of the rescue disk. So if you want to do this, you will have to mark the root LV as available, mount it, and then copy /mnt/<mountpoint>/usr/sbin/vgrename to /tmp. Then you have to unmount the root partition and mark the LV as unavailable.
rename the logical volumes
- lvrename <vgname><oldlvname> <newlvname>
repeat #5 as necessary
The lvrename binary (symbolic link) does not exit in rescue mode, so you will have to type "lvm lvrename" (and "lvm lvchange", etc.). Also, you have to use a forward slash here.
- re-activate all the lvs
- lvchange -a y <vgname>
Remember to use the new names.
- re-mount the root and boot lvs,
- mount /dev/<vgname>/<rootlv> /mnt/sysimage
- mount /dev/<vgname>/<bootlv> /mnt/sysimage/boot
I think this part worked as is.
- chroot to the mounts with, 'chroot /mnt/sysimage /bin/bash'
Before I could do this, I had to use mknod to create the device entries in /mnt/sysimage/dev/mapper/<vgname>-<lvname> and the symbolic links in /mnt/sysimage/dev/<vgname>/<lvname>. Make sure the symbolic links point to /dev/mapper/... and not /mnt/sysimage/dev/ mapper/... I don't remember if this was required to mount it while in rescue mode or to make the system bootable again. But I remember that I had to do it.
edit /etc/fstab
edit /boot/grub/grub.conf
remake the initrd
- mkinitrd -f /boot/initrd-$(uname -r).img $(uname -r)
You will have to type the release version of the kernel instead of relying on the output of uname -r.
It turns out that I can skip steps 7-12 since I plan to upgrade the systems from CentOS 4.6 to CentOS 5.1 immediately after doing the rename, and the installer (anaconda) will take care of all these details. I just had to adjust my kickstart scripts to use the new names.
Anyway, thanks again for all the help. I'm starting to upgrade my two dozen or so desktops to CentOS 5.1 using the new VG and LV names.
Alfred
Alfred von Campe wrote:
On May 2, 2008, at 17:24, Ross S. W. Walker wrote:
Sure you can do all this from rescue mode off the first CD.
Boot the cd type in 'linux rescue' and continue to the command prompt.
First, thanks for the detailed list, Ross. It was very helpful. I was able to rename both the VG and the LVs, but it was slightly more complicated than the items on the list.
- make sure swap isn't using the swap lv
- swapoff -a
What I did was say "Skip" when the rescue image asks you if you want it to find existing Linux installations and mount them under /mnt/ sysimage. The reason I did this was that if you let it mount your partitions, you need to go through a lot of additional steps to get everything under /mnt/sysimage unmounted, and nothing in there is needed to do the rename (unless you want to rename the VG -- see below).
- unmount all lvs mounted
- umount /mnt/sysimage/boot
- umount /mnt/sysimage
Not needed because of what I did in step 1, but there are additional mount points to unmount if you do let the rescue image do the mounts (do a "mount | grep sysimage" to find all the mount points).
- mark all lvs as unavailable
- lvchange -a n <vgname>
This step is indeed required unless you chose to skip the mounting of /mnt/sysimage altogether. Do a "lvm lvscan" to find out which LVs are active (and use "lvm lvchange" as described below).
- rename the volume group
- vgrename <oldvgname> <newvgname>
Well, vgrename is not part of the rescue disk. So if you want to do this, you will have to mark the root LV as available, mount it, and then copy /mnt/<mountpoint>/usr/sbin/vgrename to /tmp. Then you have to unmount the root partition and mark the LV as unavailable.
rename the logical volumes
- lvrename <vgname><oldlvname> <newlvname>
repeat #5 as necessary
The lvrename binary (symbolic link) does not exit in rescue mode, so you will have to type "lvm lvrename" (and "lvm lvchange", etc.). Also, you have to use a forward slash here.
- re-activate all the lvs
- lvchange -a y <vgname>
Remember to use the new names.
- re-mount the root and boot lvs,
- mount /dev/<vgname>/<rootlv> /mnt/sysimage
- mount /dev/<vgname>/<bootlv> /mnt/sysimage/boot
I think this part worked as is.
- chroot to the mounts with, 'chroot /mnt/sysimage /bin/bash'
Before I could do this, I had to use mknod to create the device entries in /mnt/sysimage/dev/mapper/<vgname>-<lvname> and the symbolic links in /mnt/sysimage/dev/<vgname>/<lvname>. Make sure the symbolic links point to /dev/mapper/... and not /mnt/sysimage/dev/ mapper/... I don't remember if this was required to mount it while in rescue mode or to make the system bootable again. But I remember that I had to do it.
edit /etc/fstab
edit /boot/grub/grub.conf
remake the initrd
- mkinitrd -f /boot/initrd-$(uname -r).img $(uname -r)
You will have to type the release version of the kernel instead of relying on the output of uname -r.
It turns out that I can skip steps 7-12 since I plan to upgrade the systems from CentOS 4.6 to CentOS 5.1 immediately after doing the rename, and the installer (anaconda) will take care of all these details. I just had to adjust my kickstart scripts to use the new names.
Anyway, thanks again for all the help. I'm starting to upgrade my two dozen or so desktops to CentOS 5.1 using the new VG and LV names.
Thanks for updating the points with your experience. I wrote it from memory, so was bound to miss something. Maybe it can be incorporated into a general how-to.
Yeah the lvm included in the busybox rescue is a little kludgy, that's why I typically use the FC8 rescue CD as it is a little more refined.
You can try making symlinks to 'lvm' for lvrename and vgrename or even hard links and it should provide that function.
Good idea to skip the mounting, because once it's mounted it's a PITA to umount everything and re-mount it.
Of course if your performing an upgrade there is no need to regenerate the initrd as a new one is created during install.
-Ross
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-
Alfred von Campe -
Joshua Gimer -
Ross S. W. Walker -
William L. Maltby