Create/modify a vg00 PE size=36Mb

[Aranzazu]

Hello,
I want to modify the size of the PE=16MB in vg00 to PE=108Mb.
Is is posible to chage on-line?
If it is not posible, How i cant create a vg00 with PE=108MB?

Thanks in advance.

[RAC_1]

You can not do that online. You will have to re-create the VG. PE size must be eqal to the power of 2. It can not be 108. Read the ma page carefully. It has all the details.

Why do you want to set it so high??

Anil

[Thierry Poels_1]

hi,

the PE size of a VG is defined during VG creation. You can't change it afterwards.

As it considers VG00 you'll need to reinstall the system, or restore from an Ignite tape.

But why do you need such a large PE size in VG00. VG00 is intended for OS filesystems only, and doesn't require super large filesystems or disks.

regards,
Thierry.

[Aranzazu]

Thaks for the fist question.
The fact is that I have three 142Gb disk in vg00.
My server have only 3 slots for disks.
I have to have the SO and a SAP aplication in the vg00.
I need create a lvol up to 96Gb and it must be in mirror.

Due to I have only 3 disk and all my lvols need mirror,It is necesary to take all of them in the same vg.

Besides, Max PE per PV is 4328, and i have three disk 142Gb each=total 426Gb so
I need define around 100Mb (even a litte more) PE per PV so: 100Mb per PV x 4328 max PE per PV=432800Mb=422Gb

[Stephen Keane]

> Max PE per PV is 4328

But that is because of how the VG was created, it isn't a general limit. Remember, you can have up to 65535 PE per VG.

[Sunil Sharma_1 · Accepted solution]

Your calculation about size of PE is wrong. When you say you have Disk Size 140Gb and Max PE per PV is 4384 then you have to haev PE size not more then 32MB to get full use of 140GB.

I recently installed HPUX11i on one of my server and used 140Gb disk as root disk and It work perfectly fine.

Post the output of vgdisplay vg00 here.

If you installed HPUX in 140 GB disk then Installation itself will set these parameters correct.

Sunil

[Andrew Fong]

Max PE per PV is 4384. It's for individual physical disk and not for the total of three disks.

A PE size of 32MB is sufficient for the full use of 140GB disk as suggested by Sunil.

Regards
Andrew

[Peyman Javaheri]

Hi Aranzazu,

I am following everyone that you should recreate your volume group and you don't need such high maximums.

On the other hand back to the original question, as you have assumed by now, you cannot do any of this online.

There is an unsupported offline utility by HP called vgmodify, which probably can do to some extent what you want here without recreating the VG.

Search for the word vgmodify in the ITRC forums and you will find some detailed info.

Here is a synopsis from the command's manpage:

vgmodify(1M)



NAME

vgmodify - modify an LVM volume group's attributes.

SYNOPSIS

/usr/sbin/vgmodify [-e MaxPhysicalExtents | -d DiskSize] [-p MaxPhysicalVolumes] [-l MaxLogicalVolumes] [-r] VolumeGroupName [pv_path] [pv_path] [.....]

Good luck,
peyman;

[Bill Hassell]

When SAM or vgcreate sets the number of PE's as well as the size of a PE, it is done based on the size of all the disks you are adding at the moment. So if you add more disks at a later time, the maximum number of PEs may not be enough. So you have to plan ahead by specifying the PE size and the max PE's. The maximum amount space that can be handled by a VG is:

PEsize * MaxPEs

Don't take the defaults when creating the VG, just specify the size and number of PEs. It is recommended to keep the maxPEs less than 65000, more like 40000 or less. Adjust your PEsize accordingly.