Expanding an LVM

Expanding an LVM

[Dermot Paikkos]

Hi,

I think I may have made a error in the method I have used to create 
more space on one of my servers.

Here's what I've done.

1) Backed up the LVM volume (phew)
2) Added some disks to the storage array (HP MSA 20)
3) Used the HW Array configurator to do and on-line extend of the  
Raid Array.

It was at this point I realised that I hadn't un-mounted the volume 
in question. 

The other thing I am trying to figure out is, how I am going to 
extend a Physical Volume? I think the procedure should have been to 
add a completely new array and use pvcreate, vgextend, lvextend and  
extended the filesystem (ext3).

Can anyone confirm if the procedure above is the correct? 

Right now I am considering deleting the RAID container completely and 
re-creating and restoring rather than waste any more time but before 
I do I'd like to hear it if sounds like the procedure is bound to 
fail. 

At the moment I think the best I can hope for is that the volume will 
be fine but the extra disk-space will never be seen?

Any thoughts?
Tia,
Dp.

Re: Expanding an LVM

[urgrue]

Dermot Paikkos wrote:
> Hi,
> 
> I think I may have made a error in the method I have used to create 
> more space on one of my servers.
> 
> Here's what I've done.
> 
> 1) Backed up the LVM volume (phew)
> 2) Added some disks to the storage array (HP MSA 20)
> 3) Used the HW Array configurator to do and on-line extend of the  
> Raid Array.
> 
> It was at this point I realised that I hadn't un-mounted the volume 
> in question. 
> 
> The other thing I am trying to figure out is, how I am going to 
> extend a Physical Volume? I think the procedure should have been to 
> add a completely new array and use pvcreate, vgextend, lvextend and  
> extended the filesystem (ext3).
> 
> Can anyone confirm if the procedure above is the correct? 

Correct. You dont expand the PV, you make a new partition with fdisk in
the new space and then create a pv on it, add it to the vg with
vgextend, and the lvextend and then ext2online/resize2fs/whatever to
expand the fs.

> Right now I am considering deleting the RAID container completely and 
> re-creating and restoring rather than waste any more time but before 
> I do I'd like to hear it if sounds like the procedure is bound to 
> fail. 
> 
> At the moment I think the best I can hope for is that the volume will 
> be fine but the extra disk-space will never be seen?
> 

if you dont see the new space in fdisk, you might have to reboot, or do
echo "- - -" > /sys/class/scsi_host/hostXXX/scan.

RE: Expanding an LVM

[Dermot Paikkos]

Hi,

> -----Original Message-----
> From: urgrue [mailto:urgrue@bulbous.org]
> Sent: 19 August 2008 11:27
> 
> Correct. You dont expand the PV, you make a new partition with fdisk 
in
> the new space and then create a pv on it, add it to the vg with
> vgextend, and the lvextend and then ext2online/resize2fs/whatever to
> expand the fs.

> > Right now I am considering deleting the RAID container completely 
and
> > re-creating and restoring rather than waste any more time but before
> > I do I'd like to hear it if sounds like the procedure is bound to
> > fail.
> >
> > At the moment I think the best I can hope for is that the volume 
will
> > be fine but the extra disk-space will never be seen?
> >
> 
> if you dont see the new space in fdisk, you might have to reboot, or 
do
> echo "- - -" > /sys/class/scsi_host/hostXXX/scan.

Do you mean the new space on the expanded RAID logical drive or a 
completely new RAID container?

Thanx,
Dp.

Re: Expanding an LVM

[urgrue]

Dermot Paikkos wrote:
> Hi,
> 
>> -----Original Message-----
>> From: urgrue [mailto:urgrue@bulbous.org]
>> Sent: 19 August 2008 11:27
>>
>> Correct. You dont expand the PV, you make a new partition with fdisk 
> in
>> the new space and then create a pv on it, add it to the vg with
>> vgextend, and the lvextend and then ext2online/resize2fs/whatever to
>> expand the fs.
> 
>>> Right now I am considering deleting the RAID container completely 
> and
>>> re-creating and restoring rather than waste any more time but before
>>> I do I'd like to hear it if sounds like the procedure is bound to
>>> fail.
>>>
>>> At the moment I think the best I can hope for is that the volume 
> will
>>> be fine but the extra disk-space will never be seen?
>>>
>> if you dont see the new space in fdisk, you might have to reboot, or 
> do
>> echo "- - -" > /sys/class/scsi_host/hostXXX/scan.
> 
> Do you mean the new space on the expanded RAID logical drive or a 
> completely new RAID container?
> 

I mean the new space on the existing RAID drive. If you used the RAID
tools to expand the existing array onto the same logical drive as
before, then from linux's point of view the underlying disk just "got
bigger", and it may require a reboot or the scsi scan i mentioned to get
linux to notice.
If you made a new logical drive, then it will appear as a new disk (in
linux). This too will require either a reboot or the scsi scan.
Either way, you then have to use fdisk to make a partition on the new
space and then pvcreate etc.