Question: Multiple volume groups on one disk?

[Angie_1]

Hi..

I have 1 36-gig drive. I am planning to install 10.20 (have to due to application). I want to though have 10.20 in VG00 and something else in VG01 but on the same disk.
Can this be done? Or do you have to allocate an entire volume group for one disk?

Please respond.

Thanks, Angie

[Patrick Wallek · Accepted solution]

Nope, this can not be done. When you set up a VG, the ENTIRE disk is part of that VG.

A VG can be made up of multiple drives. But 1 drive can NOT be a part of multiple VGs

Your best (read only) option would be to set up another LVOL as part of VG00 for your application.

[Pete Randall]

Angie,

As Patrick said, a physical disk can only be long to one VG. That said, however, I would strongly encourage you to keep additional lvols (which I presume will contain application data), separate from your vg00. Keeping vg00 strictly for your root volume, even if it means wasting some disk space, is highly desirable when it comes to backup and recovery efforts.


Pete

[James R. Ferguson]

Hi Angie:

No. A volume group consists of one or more physical disks but is uniquely identified by an LVM header written to every physical disk member. You may, however, have an arbitrary number of logical volumes within any volume group. See the 'lvm(7)' man pages for more information. See also, the "Managing Systems and Workgroups: A Guide for HP-UX System Administors" guide (chapter-6) for an excellent introduction to LVM.

Regards!

...JRF...

[Helen French]

No. You cannot have multiple VGs on the same PV. You have to allocate the entire disk for a single VG. Read man pages of:

# man vgcreate

Also, check the LVM rules for all possible limitations and conditions.

[Angie_1]

Hi all..

Thanks for the quick responses.
Ok I will just have VG00 for the OS.
But I was confused on the below. Is this saying that I should set up like a different VG# in order to have the additional lvols? In other words, I must set up Vg01 on another disk for these additional lvols, right?
I guess though I could have Vg00 lvol15 have the data but it then would be a part of the same Volume group.

Thanks...Angie

" I would strongly encourage you to keep additional lvols (which I presume will contain application data), separate from your vg00."

[Steven E. Protter]

I have never been able to figure out how to do it. That means its probably impossible as noted earlier.

Its a growing complaint now that the new servers are shipped with gigantic internal drives.

SEP

[Pete Randall]

Angie,

>"In other words, I must set up Vg01 on another disk for these additional lvols, right? "


Exactly right. If you're really tight on space, you could use the leftover space on vg00 for additional lvols, but you would be better off to keep things separate if you can and keep vg00 strictly for your root volume.


Pete

[Helen French]

For the last question: Unless it's very necessary, I would suggest you to put all your application and data on a different VG other than vg00. This will be helpful incase of a OS recovery, application recovery, application file system resizing, OS mirroring etc ..etc ..

Btw, 10.20 is no longer supported by HP. Consider installing 11.0 or 11i on the system.

[Angie_1]

Thank you all!!!

I got all my questions answered. Will try to keep the OS only on VG00.

Thank you again... you are all so wonderful.

Angie