topic vg extend in Operating System - HP-UX

vg extend

A.G.M. Velthof — Tue, 17 Feb 2004 10:26:51 GMT

Hello all,

when I try to extend a mirrored volume group
of 17 GB with another 17 GB disk I get a message: "Disk MBytes More then VG can support - continue anyway?"

Anyone any idea what is happening?

Re: vg extend

G. Vrijhoeven — Tue, 17 Feb 2004 10:33:13 GMT

Hi,

The vg accept all disks but is only able to use diskpace ( MAX PE per PV * PE Size). This is default the size of the first disk added to the vg. If that is smaller as the disk you try to add you are not able to use all the disk space on the new disk.

You can not alter those sizes. Your only option in fbackup remove current vg, create new one and lvrecover.

HTH,

Gideon

Re: vg extend

Steve Steel — Tue, 17 Feb 2004 10:33:14 GMT

Hi

I have been there

This happens when you attempt to add a physical volume to a VG and the PV size exceeds the limit on the vg(max PE per PV).

Sorry but you must remake it

Steve STeel

Re: vg extend

Robert-Jan Goossens — Tue, 17 Feb 2004 10:35:49 GMT

Hi,

Check the output from

# vgdisplay -v your_vg

and check for these notes

Max PE per PV 4350

PE Size (Mbytes) 4

This means your disk is probably to large for your volume group. I my case above 18 GB disks.

Regards,
Robert-Jan

Re: vg extend

Everett R. Stroman — Wed, 18 Feb 2004 07:25:58 GMT

Hello,

This error is received when attempting to add a physical volume to a volume
group and the size of the physical volume exceeds the disk size limit on the
volume group (max PE per PV).

Since I dont know what size your disk is lets assume, the PE size is 4 Mbytes and the Max PE per PV limit is set to 1016. This means that the largest disk that can be added to the volume group is 4064 Mbytes. The disk that is being added to the volume
group is larger than the disk that was used when the volume group was created, the disk is added fine but you will only be able to used 4064 Mbytes of its space.

This limit (max PE per PV) defaults to 1016 when the volume group is created (see the vgcreate(1M) man page, -e option). This parameter can be adjusted by either using the '-e' option with vgcreate, or creating the volume group with the largest disk you plan to have in the volume group - this value will automatically be increased to match the size of the disk when the volume group is created.

The only way to adjust this parameter on an established volume group is to recreate the volume group, requiring:

1. Backup the data in the file systems

2. lvreduce out the logical volumes

3. vgreduce out the physical volumes

4. vgremove the volume group

5. vgcreate the volume group with the -e option to increase the max PEs
per PV (or vgcreate-ing the volume group with the larger disk)

6. vgextend the physical volumes back in

7. lvcreate the logical volumes

8. newfs the file systems within those logical volumes

9. Restore the data to the file systems

The reason that this parameter cannot be changed dynamically is because it is used to calculate the size of the PE-to-LE mapping information kept in the Volume Group Reserve Area. The formula used is:

2*max_pe*max_pv*(extent size)

Good luck,

Everett

Re: vg extend

A.G.M. Velthof — Wed, 18 Feb 2004 07:34:18 GMT

Thanks for the reply's.
I will recreate the volumegroup on the 2 new disks and restore the data.