[linux-lvm] Removing a very old physical drive

[linux-lvm] Removing a very old physical drive

[Nicholas Robinson]

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?

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?

3. Where has the LogVol01 come from and what is it doing? Can I remove
it?

4. Can I rename the volgroup/logvols to the same pattern used by new
installations? e.g. vg_hostname and lv_root, etc.

If you've read this far, then thank you! I hope the following extracts
are sufficient.

Best Wishes

Nick

# pvdisplay
  --- Physical volume ---
  PV Name               /dev/sdb2
  VG Name               VolGroup00
  PV Size               27.76 GB / not usable 13.73 MB
  Allocatable           yes 
  PE Size (KByte)       32768
  Total PE              888
  Free PE               30
  Allocated PE          858
  PV UUID               V7XQmw-wMkv-fA4H-UUzn-d4CR-sfju-jHYjNZ
   
  --- Physical volume ---
  PV Name               /dev/sda2
  VG Name               VolGroup00
  PV Size               315.00 GB / not usable 31.81 MB
  Allocatable           yes 
  PE Size (KByte)       32768
  Total PE              10079
  Free PE               987
  Allocated PE          9092
  PV UUID               tXBnAO-0D0U-yLvg-XhaA-vEw3-Niz7-p23dAt
   
  "/dev/sda1" is a new physical volume of "298.09 GB"
  --- NEW Physical volume ---
  PV Name               /dev/sda1
  VG Name               
  PV Size               298.09 GB
  Allocatable           NO
  PE Size (KByte)       0
  Total PE              0
  Free PE               0
  Allocated PE          0
  PV UUID               T1XNow-VO83-JVW5-8NBh-1fiF-VzWT-m5mj2P

# fdisk -l /dev/sda

Disk /dev/sda: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Disk identifier: 0x30b7d346

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1           6       48163+  83  Linux
/dev/sda2               7       38913   312520477+  83  Linux

# lvdisplay
  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol00
  VG Name                VolGroup00
  LV UUID                LPxYrN-E62m-L8uh-Ms0O-vZNI-EWM6-GlBD4E
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                310.00 GB
  Current LE             9920
  Segments               3
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:0
   
  --- Logical volume ---
  LV Name                /dev/VolGroup00/LogVol01
  VG Name                VolGroup00
  LV UUID                u3rWh0-NHxf-pn3F-o0Du-Mbnw-LG5V-2l2t3T
  LV Write Access        read/write
  LV Status              available
  # open                 1
  LV Size                960.00 MB
  Current LE             30
  Segments               1
  Allocation             inherit
  Read ahead sectors     auto
  - currently set to     256
  Block device           253:1

# df
Filesystem           1K-blocks      Used Available Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
                     314908972 145080044 153584540  49% /
/dev/sdb1               198129     13938    173962   8% /boot
tmpfs                   239080         0    239080   0% /dev/shm

Re: [linux-lvm] Removing a very old physical drive

[Matthew Gillen]

On 10/26/2009 04:59 AM, Nicholas Robinson 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.
> ...

> 1. Can I do move the data off the old drive to the new drive without
> adding another new drive?

Is there any reason you can't use 'cp -a'?  If that isn't an option for some
reason, then you're out of luck, if I understood correctly: if the new disk is
completely allocated to another VG and you can't free up some partition (PV)
to add to the 'old' VG, there's not much you can do, AFAIK (since any given
partition/PV can only belong to one VG).

> 3. Where has the LogVol01 come from and what is it doing? Can I remove
> it?

Given your potentially flaky memory, it might be wise to try mounting it
somewhere first to see what's on it... ;-)

> 4. Can I rename the volgroup/logvols to the same pattern used by new
> installations? e.g. vg_hostname and lv_root, etc.

The GUI tool in fedora (system-config-lvm) appears to allow you to change the
names of VGs, presumably it's also possible from the command line.  Just be
sure that your /etc/fstab is consistent with whatever changes you make.

HTH,
Matt

Re: [linux-lvm] Removing a very old physical drive

[malahal]

Nicholas Robinson [npr@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.

> 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!

> 3. Where has the LogVol01 come from and what is it doing? Can I remove
> it?

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.

Re: [linux-lvm] Removing a very old physical drive

[Ray Morris]

    I think you want "pvmove".  It moves LVs off of a physical
volume onto other ones in the same volume group.

> 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

    The drive is fully allocated and it has plenty of free
space?  Do you mean that the drive is part of the volume
group, but does not yet have all it' sectors full?
--
Ray Morris
support@bettercgi.com

Strongbox - The next generation in site security:
http://www.bettercgi.com/strongbox/

Throttlebox - Intelligent Bandwidth Control
http://www.bettercgi.com/throttlebox/

Strongbox / Throttlebox affiliate program:
http://www.bettercgi.com/affiliates/user/register.php


On 10/26/2009 03:59:58 AM, Nicholas Robinson 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?
> 
> 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?
> 
> 3. Where has the LogVol01 come from and what is it doing? Can I remove
> it?
> 
> 4. Can I rename the volgroup/logvols to the same pattern used by new
> installations? e.g. vg_hostname and lv_root, etc.
> 
> If you've read this far, then thank you! I hope the following extracts
> are sufficient.
> 
> Best Wishes
> 
> Nick
> 
> # pvdisplay
>   --- Physical volume ---
>   PV Name               /dev/sdb2
>   VG Name               VolGroup00
>   PV Size               27.76 GB / not usable 13.73 MB
>   Allocatable           yes
>   PE Size (KByte)       32768
>   Total PE              888
>   Free PE               30
>   Allocated PE          858
>   PV UUID               V7XQmw-wMkv-fA4H-UUzn-d4CR-sfju-jHYjNZ
> 
>   --- Physical volume ---
>   PV Name               /dev/sda2
>   VG Name               VolGroup00
>   PV Size               315.00 GB / not usable 31.81 MB
>   Allocatable           yes
>   PE Size (KByte)       32768
>   Total PE              10079
>   Free PE               987
>   Allocated PE          9092
>   PV UUID               tXBnAO-0D0U-yLvg-XhaA-vEw3-Niz7-p23dAt
> 
>   "/dev/sda1" is a new physical volume of "298.09 GB"
>   --- NEW Physical volume ---
>   PV Name               /dev/sda1
>   VG Name
>   PV Size               298.09 GB
>   Allocatable           NO
>   PE Size (KByte)       0
>   Total PE              0
>   Free PE               0
>   Allocated PE          0
>   PV UUID               T1XNow-VO83-JVW5-8NBh-1fiF-VzWT-m5mj2P
> 
> # fdisk -l /dev/sda
> 
> Disk /dev/sda: 320.0 GB, 320072933376 bytes
> 255 heads, 63 sectors/track, 38913 cylinders
> Units = cylinders of 16065 * 512 = 8225280 bytes
> Disk identifier: 0x30b7d346
> 
>    Device Boot      Start         End      Blocks   Id  System
> /dev/sda1   *           1           6       48163+  83  Linux
> /dev/sda2               7       38913   312520477+  83  Linux
> 
> # lvdisplay
>   --- Logical volume ---
>   LV Name                /dev/VolGroup00/LogVol00
>   VG Name                VolGroup00
>   LV UUID                LPxYrN-E62m-L8uh-Ms0O-vZNI-EWM6-GlBD4E
>   LV Write Access        read/write
>   LV Status              available
>   # open                 1
>   LV Size                310.00 GB
>   Current LE             9920
>   Segments               3
>   Allocation             inherit
>   Read ahead sectors     auto
>   - currently set to     256
>   Block device           253:0
> 
>   --- Logical volume ---
>   LV Name                /dev/VolGroup00/LogVol01
>   VG Name                VolGroup00
>   LV UUID                u3rWh0-NHxf-pn3F-o0Du-Mbnw-LG5V-2l2t3T
>   LV Write Access        read/write
>   LV Status              available
>   # open                 1
>   LV Size                960.00 MB
>   Current LE             30
>   Segments               1
>   Allocation             inherit
>   Read ahead sectors     auto
>   - currently set to     256
>   Block device           253:1
> 
> # df
> Filesystem           1K-blocks      Used Available Use% Mounted on
> /dev/mapper/VolGroup00-LogVol00
>                      314908972 145080044 153584540  49% /
> /dev/sdb1               198129     13938    173962   8% /boot
> tmpfs                   239080         0    239080   0% /dev/shm
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/
> 
> 

Re: [linux-lvm] Removing a very old physical drive

[Nicholas Robinson]

On Mon, 2009-10-26 at 09:10 -0700, malahal@us.ibm.com wrote:
> Nicholas Robinson [npr@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.
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] Removing a very old physical drive

[malahal]

Nicholas Robinson [npr@bottlehall.co.uk] wrote:
> > 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.

Allocated PEs is the number of PEs allocated to logical volumes, Free
PE's is the number PEs not yet allocated. Free PEs+Allocated PEs =
Total PEs.  I think you have enough free PEs to cover the old drive if I
remember your output correctly.

> 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!

That explains why the '#open count is 1" in your lvdisplay output!

Thanks, Malahal.

Re: [linux-lvm] Removing a very old physical drive

[Nicholas Robinson]

Help!

I did the pvremove command and everything seemed fine. I carried on
working on the first question and tried to do the pvmove

Immediately the machine hung and when I try to reboot, it finds the boot
partition and begins the boot, but then hangs with a blank screen and
top-left cursor. Occasionally, I can stop it with some messages about
dm-1 and logical block 0 to 8 missing.

I wonder if the pvremove over-wrote something important on the other
partition as it had an incorrect view of the size of the sda1?

Thanks

Nick


On Mon, 2009-10-26 at 09:10 -0700, malahal@us.ibm.com wrote:
> Nicholas Robinson [npr@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.
> 
> > 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!
> 
> > 3. Where has the LogVol01 come from and what is it doing? Can I remove
> > it?
> 
> 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.
> 
> _______________________________________________
> linux-lvm mailing list
> linux-lvm@redhat.com
> https://www.redhat.com/mailman/listinfo/linux-lvm
> read the LVM HOW-TO at http://tldp.org/HOWTO/LVM-HOWTO/

Re: [linux-lvm] Removing a very old physical drive

[malahal]

Nicholas Robinson [npr@bottlehall.co.uk] wrote:
> Help!
> 
> I did the pvremove command and everything seemed fine. I carried on
> working on the first question and tried to do the pvmove
> 
> Immediately the machine hung and when I try to reboot, it finds the boot
> partition and begins the boot, but then hangs with a blank screen and
> top-left cursor. Occasionally, I can stop it with some messages about
> dm-1 and logical block 0 to 8 missing.

Culprit seems to be pvmove. Get a liveCD and try to activate the VG and
see if you can mount the LV. You can read of the LVM metadata from the
disk partitions (PVs). This is really sad and you need lot more LVM
expertise to fix things.
 
> I wonder if the pvremove over-wrote something important on the other
> partition as it had an incorrect view of the size of the sda1?

Even if pvremove tries to write something beyond /dev/sda1's size, the
write would fail. It can't do anything other than writing to /dev/sda1.
In other words, it can't mess with /dev/sda2.

Re: [linux-lvm] Removing a very old physical drive

[malahal]

postmaster@bottlehall.eclipse.co.uk [postmaster@bottlehall.eclipse.co.uk] wrote:
>    Fixed it!
> 
>    Rummaging around with dmsetup, I discovered that lvm wasn't making the
>    pvmove lv active - it was suspended. It seems everything trying to run
>    against it was waiting for it to unsuspend. Using dmsetup to resume it
>    then meant that pvmove --abort worked and then a normal re-boot followed.

That is good to know!

Thanks, Malahal.