[linux-lvm] Removing a very old physical drive

Nicholas Robinson npr at bottlehall.co.uk
Mon Oct 26 19:29:14 UTC 2009


On Mon, 2009-10-26 at 09:10 -0700, malahal at us.ibm.com wrote:
> Nicholas Robinson [npr at bottlehall.co.uk] wrote:
> > Hi
> > 
> > I've been using lvm for quite a few years, but only occasionally when I
> > need to add/remove new drives. So, my knowledge is limited and a bit
> > rusty! I should have removed the old drive when I added a new one a
> > couple of years ago, but for reasons I cannot remember, I didn't.
> > 
> > I only know how to remove a drive when there is a new drive about to
> > move the stuff onto. My problem now is that the new drive is fully
> > allocated and so this route won't work. There is plenty of free space on
> > the new drive so it should be possible to move everything that might be
> > on the old physical drive and then remove it from the lvg. I just can't
> > work out how. The HOWTOs and threads don't seem to cover this starting
> > point.
> > 
> > My questions are:
> > 
> > 1. Can I do move the data off the old drive to the new drive without
> > adding another new drive?
>  
> pvmove followed by vgreduce. If you have enough free space, pvmove
> should work and there is no need to add another new drive.
> 
Thanks, I will give this a go. I think I was getting confused between
allocated and used. I thought the destination PV had to have enough
unallocated extents on it to absorb the old PV data rather than just
unused.

> > 2. I don't understand the output from pvdisplay - why is it telling me
> > about /dev/sda1 at the bottom when this partition is a boot partition
> > and tiny?
> 
> It also reports a large size! Somehow, it detected PV signature in that
> partition. You can remove such signature by running pvremove. Note that
> it wipes out LVM label, so back up your data in /dev/sda1 somewhere else
> before you run "pvremove /dev/sda1". If the partition is mountable after
> 'pvremove', you are fine. Otherwise restore the backup!
> 
Although it is listed as a boot partition in fdisk -l, it is not
currently used. The old disc is still the boot disc and so /dev/sda1 is
not being used at all. I can safely do a pvremove and make this
partition the real boot partition.

> > 3. Where has the LogVol01 come from and what is it doing? Can I remove
> > it?
> 
I tried mounting it as you suggest and it muttered about it looking like
swap. So, I checked and it is mounted as swap! That explains that one.
The newer naming convention of ...lv_swap would have made this much
clearer!

> Try mounting it and see if there is anything there. You can use lvremove
> if you don't need it.
> 
> > 4. Can I rename the volgroup/logvols to the same pattern used by new
> > installations? e.g. vg_hostname and lv_root, etc.
> 
> Yes, see lvrename and vgrename commands.
>  
> > If you've read this far, then thank you! I hope the following extracts
> > are sufficient.
> 
> You are welcome.
> 
You are very kind. I have printed your reply out and will follow it
carefully. Thank you very much.
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> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/




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