expandig a volume group on and EVA and unix server

[richard Nahhas]

Hello All,
I have volumes created on an EVA 3000 and configured on a HPUX server, in fact on of the volumes is about 8GB and i need to extend it to 20 GB, i want to expend the same disk created on the EVA3000 and it is possible by command view, but i want to know how to extend it on the unix systems.
with the vgextend i can add another disk to the volume group, but is there a possibility to extend the volume group on the same disk if the new size of the disk is 20 GB on the EVA now and not 8GB.
Thank you

[Hoefnix]

I don't know how this really is going to act but I think you will see more Free PE in you vgdisplay results after doing the VA-disk resize.

I would make a backup before doing this action, but if the resize does not effect the current used PE on the VA LUN it should work.


Regards,

Peter

[richard Nahhas]

Hello,
i fact when i reactivated the volume group and make a vgdisplay -v vgdisk6 i have got the same PE and size of the volume group nothing has chaged .
i don't know if there is a way to extend the number of PE ?
thank you

[Stefan Farrelly]

There is no way to extend the VG to add in a 20GB drive if it was created originally only for an 8GB drive max. The VG parameters need to be increased, and the only way to do this is to destroy your VG and recreate (adding the largest 20GB disk in first), or create a new VG with the 20GB lun/disk.

An alternative is to break down your new 20GB lun into 8GB pieces and add each into your existing VG, then you can increase the lvol and filesystem on the fly (using fsadm).

In future with EVA's there is going to be some software which will allow dynamic increasing of a lun on he fly, ie. you increase the size of an existing lun on the EVA (not add in a new one) and the VG and LV will automatically resize to the new larger lun size. Very handy - but I dont believe its available yet.

[Elmar P. Kolkman]

Problem is that the number of PE's is limitted at the time you run the pvcreate or vgcreate... At least the number of PE's is limited by the time you add the disk to the vg.

First check the vgdisplay output for the maximum number PE's per PV. It should be at least 5000 with a PE size of 4Mb to support 20Gb disks.

If that number is high enough, you need to re-add the disk, probably with a new pvcreate. Mirroring is your friend for this...

[Elmar P. Kolkman]

As for Steven's reply: see the vgmodify thread of last week.
But I hope the lvol's don't expand automatically if a LUN expands. Sometimes you expand a LUN to create new lvols in a vg.

[Hoefnix]

....sorry, like the other say, you are limitted by the PE limits you gave up with creating the VG :(

[Fabio Ettore]

Hi,

(as Stefan already said) increasing PE SIZE is only possible at the moment of the creation of a volume group and it is needed when managing big volume groups (with big sizes of disks/LUNs):

# vgcreate -s PE_SIZE /dev/vgXX /dev/dsk/cXtXdX

In your instance I think the following value:

# vgcreate -s 8 /dev/vgXX /dev/dsk/cXtXdX

From man page of vgcreate:

-s pe_size Sets the number of megabytes in each physical
extent, where pe_size is expressed in units
of megabytes (MB) in the range 1 to 256.
pe_size must be equal to a power of 2 (1, 2,
4, 8, etc.). The default value for pe_size
is 4 (four megabytes).


Best regards,
Ettore

[Kevin.Wang]

I met the same problem recently, who can resolve it?