vgextend problems

[Michael Moore_3]

Add an 18GB disk to a new volume group which I create,and view that physical volume using vgdisplay,correct number of PE's (Physical Extents are shown).

Remove that disk from the volume group that I have just created using vgreduce ,in order to add it to vg00 using vgextend.

When adding disk to vg00 with vgextend the number of PE's is far short of what it should be.

Disks in vg00 are also 18gb disks,but are mirrored.

Does the fact that the disks in vg00 are mirrored have any bearing on why the number of PE's falls way short of what they should be ?

Thanks Michael

[James R. Ferguson]

Michael:

I suspect that your existing volume group is made up of one or more 4GB or maybe 8GB disks. When this was originally created, the max_pe parameter to vgcreate was not specified, and the default value was used. This default is no larger than the largest disk present during VG creation. Since max_pe can't be changed afterwards, extending a volume group with very large disks leads to a "loss" of physical extents.

...JRF...

[James R. Ferguson]

Michael:

...I should have also added, that the fact that you DO see all physical extents for the disk when you vgcreate a fresh volume group is consistent and expected behavior for what you describe.

...JRF...

[John Palmer]

It's curious that you have 18Gb disks in vg00 already. Could you post the output from

vgdisplay -v vg00

[MARTINACHE]

If you need to change the MAX_PE_PER_PV parameter for vg00, you can do it whith an ignite tape restore.

I suggested you te create an ignite tape :
make_recovery -ACi

With -i option, after the boot on the tape, you go directly to the recovery menu.

Under the filesystem menu->Advanced Task
You can change vg parameters.

(Sorry for my bad english ...)

Patrice.