vgextend: Warning: Max_PE_per_PV

[Jojo Castro]

Hi all...

I have rx8640 running on HP-UX11.23.
I configured a file systems using LVM in "SAM."
The device I used is from EMC storage DMX.
LUN size capacity is 25GB.
I initialy mounted this file system as 20GB.
Our developer requested to increase the size of this file system.
And then I use a device with LUN size of 69GB.
When I tried to vgextend the the volume group of this file system, I encountered the follwing error:

# pvcreate /dev/rdsk/c8t10d5
Physical volume "/dev/rdsk/c8t10d5" has been successfully created.
# hostname
AURA01
# vgextend vggxarch1 /dev/dsk/c8t10d5
vgextend: Warning: Max_PE_per_PV for the volume group (1287) too small for this PV (4351).
Using only 1287 PEs from this physical volume.
Volume group "vggxarch1" has been successfully extended.
Volume Group configuration for /dev/vggxarch1 has been saved in /etc/lvmconf/vggxarch1.conf

Using SAM, I encountered this message:
At least one of the disks you have chosen is larger than the maximum disk size allowed by volume group

It says that I can only use the 20GB out of 69GB I joined on the volume group.

Please enlighten me and if there is a chance I can use the remaining free size (49GB) of the newly added/configured device.

Thanks!

[James R. Ferguson · Accepted solution]

Hi:

The warning message is self-explanatory when you understand that the LVM header geometry is fixed during the original 'vgcreate'. That is, at the point, probably by default) you allowed only 1287 physical extents per physical volume. There are options to control this when you perform the 'vgcreate', most notably '-e max_pe' in conjunction with '-s pe_size'. See the manpages for 'vgcreate' for more information.

You have three options:

1. Accept the inability to use all of the physical extents on the physical disk just added to your volume group [not necessary!].

2. Backup your data on the volume group; destroy it and recreate it providing 'vgcreate' options like '-e max_pe', '-s pe_size' and probably '-p max_pv'.

3. Since you are running 11.23, download and install the following patches (whch require a reboot). These patches enable a new LVM command called 'vgmodify' which allows you to dynamically resize the LVM header so that in your case you *can* use all of the physical extents you have.

PHCO_36744
PHKL_31500
PHKL_32095

Manpages accompany the 'vgmodify'. You can also read more about it in this 11.31 whitepaper.

http://www.docs.hp.com/en/LVM-11iv3features/LVM_New_Features_11iv3.pdf

The patches I cited back-port the 11.31 command to 11.23.

Regards!

...JRF...

[Jojo Castro]

Thanks very much james.

[Jojo Castro]

Appreciate the help...
Thanks!