HP LVM

 
Sharish
Occasional Contributor

HP LVM

Using HP LVM,if need to extend a Volume Group with 8.3gb lunS. Will addition of few 25.4 Gb Lun create any issues.

Please give your views.
6 REPLIES 6
Muthukumar_5
Honored Contributor

Re: HP LVM

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=6289

will help you.

--
Muthu
Easy to suggest when don't know about the problem!
Pete Randall
Outstanding Contributor

Re: HP LVM

You probably won't be able to use more than 8.3gb of your 25.4gb LUN because your max PE per PV and PE size are set to your 8.3 gb LUN size. The only way to fix this is to remove and recreate your vg, specifying a higher PE size and/or increasing the Max PE per PV.


Pete

Pete
Prashanth.D.S
Honored Contributor

Re: HP LVM

Hi Sharish,

You have to see the o/p of vgdisplay. If PE size * max. no of PEs/PV is less than 25GB, then it may not be possible to extend you will have to remove the VG and recreate.

Prashanth
Senthil Kumar .A_1
Honored Contributor

Re: HP LVM

Hi Sharish,


Why don't you add the 25.4 GB luns anyway to that volume group and check, how many PE's from 25.4 GB has recognised.

You do not require to recreate the VG, as it would calculate the number of PE's for 25.4 GB automatically, based on PE size (PE size is unchangeable, needs recreation to change PE size change).

Anyway this action wouldn't cause any issue. aswell u can revert back by doing a vgreduce.

Regards,
Senthil.
Let your effort be such, the very words to define it, by a layman - would sound like a "POETRY" ;)
Sivakumar TS
Honored Contributor

Re: HP LVM

Hi,

the max size of a LUN can be calculated with the follwing

PE size ---> default is 4 MB
max PE per PV ---> 65535

The MAX size of a LUN = PE size * PEs per PV

So if you have a less PE size, it stops you from adding a BIG lun.

Regards,

Siva.
Nothing is Impossible !
Ajitkumar Rane
Trusted Contributor

Re: HP LVM

Sharish,

According to the definitions :
The maximum number of physical extents allowed per physical volume is 65,535.
But when you have created a VG the max PEs/VG is proportional to your disk size.

In your case check vgdisplay o/p for the VG you want to extend. get the PE/VG and PE size parameter multiply them to get the size of the disk that can be used in the VG.

the only option u would have is to create a new VG on the 25gb disk, maybe u can then copy the data to the 25gb disk and eventuly add the 8gb disk to this new VG.

Rgds,

Ajit

Amidsts difficulties lie opportunities