topic Re: 3 drives in a volume group in Operating System - HP-UX

3 drives in a volume group

mike worrell — Mon, 22 Apr 2002 19:14:28 GMT

HI all,
I 'm stumped again. Like everyone we are under budget restraints and have to use what parts we have to save $$.

We have 3 jamaica slots left to create a volume group for our dba's data.
Here is the deal:
3 slots
we have 2 - 9gb drives
we have 1 - 18 gb drive
About 14 gb of data take up the 2 9gb drives.
She wanted her data mirrored. SO I decided the 18gb drive would serve as my mirror for the data from the 2 - 9gb drives.
Added all 3 drives to a volgroup.
Went to mirror the data and after about 8.5gb it quit saying np more free pe's.
Did a pvdisplay on the 18gb and it says
PE size mb 4
Total pe 2171
Did a diskinfo and it shows 17782240 kb.
How come the pvdisplay doesn't recognize it as being an 18gb drive?
Is there a work around to get this 18gb drive to be able to serve as my mirror off of the 2 - 9gb drives???

Thanks for any help you can give me
Mike

Re: 3 drives in a volume group

A. Clay Stephenson — Mon, 22 Apr 2002 19:17:41 GMT

The problem is that there were not enough PE's allocated to allow for the full usage of the 18GB drive. You need to turn the world around and create the VG using the 18GB drive and then extend it using the 9GB drives and you will be able to do the mirroring.

Re: 3 drives in a volume group

Patrick Wallek — Mon, 22 Apr 2002 19:18:22 GMT

The problem is your MAX PE PER PV attribute in the VG. It is set so that the max number of PEs is only large enough for the 9GB drives, not the 18GB drive.

To fix this you have to recreate the VG and either change the initial value of MAX PE PER PV or add the 18GB drive to the VG first so that the default value is set large enough.

For more details on MAX PE PER PV and changing the default at VG creation time see 'man vgcreate'.

Re: 3 drives in a volume group

Sandip Ghosh — Mon, 22 Apr 2002 19:20:33 GMT

Actually you have created the volume group with 9 GB drive. So it had taken the max PE per PV as the maximum PE available on the 9 GB drive.

In your case you should have created the volumegroup with 18 GB drive first and then add the 9GBs or you could have given vgcreate -e .

Now you have to recreate the volumegroup.

Sandip

Re: 3 drives in a volume group

Jeff Schussele — Mon, 22 Apr 2002 19:20:44 GMT

Hi Mike,

Sorry you've hit the "PE per PV wall". PE/PV is set when the VG is created. So you have to recreate the VG - setting a higher PE/PV value when you do so.
Do so using the 18 GB as the first drive & the system will give you a proper value.

Rgds,
Jeff

Re: 3 drives in a volume group

S.K. Chan — Mon, 22 Apr 2002 19:21:14 GMT

First time creation of a VG will determined its max PE and if you added a higher capacity disk to an existing VG which was created from a lower capacity disk, this is what you would see.

Re: 3 drives in a volume group

mike worrell — Mon, 22 Apr 2002 19:33:26 GMT

thanx to all for your help.
I'll give that a try.