Unable to extent the physical volume

[amsethi]

Hi All

Scenario HPUX 11i version
I have created a volume group using 5 physical disks and then moved all my data to 5 new physical disks successfully. The new physical disks [3GB] have more space than the previous one [2GB] but I not able to extent the physical volumes.
I tried the following steps to extend my physical volume but not succeeded in doing so:

1- # pvchange -x y /dev/dsk/c13t0d0
Physical volume "/dev/dsk/c13t0d0" has been successfully changed.
Volume Group configuration for /dev/vghds has been saved in /etc/lvmconf/vghds.conf

2- # vgextend -x y /dev/vghds /dev/dsk/c15t0d0
Current path "/dev/dsk/c15t0d0" is an alternate link, skip.
Current path "/dev/dsk/c15t0d1" is an alternate link, skip.
Current path "/dev/dsk/c15t0d2" is an alternate link, skip.
Current path "/dev/dsk/c15t0d3" is an alternate link, skip.
Current path "/dev/dsk/c15t0d4" is an alternate link, skip.
vgextend: The physical volume "/dev/dsk/c15t0d0" is already recorded in the "/etc/lvmtab" file.

3- # vgdisplay -v vghds
--- Volume groups ---
VG Name /dev/vghds
VG Write Access read/write
VG Status available
Max LV 255
Cur LV 1
Open LV 1
Max PV 16
Cur PV 5
Act PV 5
Max PE per PV 1016
VGDA 10
PE Size (Mbytes) 4
Total PE 2555
Alloc PE 2555
Free PE 0
Total PVG 0
Total Spare PVs 0
Total Spare PVs in use 0

--- Logical volumes ---
LV Name /dev/vghds/lvhds
LV Status available/syncd
LV Size (Mbytes) 10220
Current LE 2555
Allocated PE 2555
Used PV 5


--- Physical volumes ---
PV Name /dev/dsk/c13t0d0
PV Name /dev/dsk/c15t0d0 Alternate Link
PV Status available
Total PE 511
Free PE 0
Autoswitch On

PV Name /dev/dsk/c13t0d1
PV Name /dev/dsk/c15t0d1 Alternate Link
PV Status available
Total PE 511
Free PE 0
Autoswitch On

PV Name /dev/dsk/c13t0d2
PV Name /dev/dsk/c15t0d2 Alternate Link
PV Status available
Total PE 511
Free PE 0
Autoswitch On

PV Name /dev/dsk/c13t0d3
PV Name /dev/dsk/c15t0d3 Alternate Link
PV Status available
Total PE 511
Free PE 0
Autoswitch On

PV Name /dev/dsk/c13t0d4
PV Name /dev/dsk/c15t0d4 Alternate Link
PV Status available
Total PE 511
Free PE 0
Autoswitch On

#


----

But I am able to see those free PE's on the new disks. Is I am doing something wrong.
Please help me in resolving this and let me know for more information.

[Patrick Wallek]

I am unclear on what it is you are trying to do. According to your vgdisplay output /dev/dsk/c13t0d[0-4] and /dev/dsk/c15t0d[0-4] are alternate paths for the same disk devices (c13t0d0 is the same device as c15t0d0 ; same goes for devies d1 thru d4 for c13t0 and c15t0).

To add more space to the VG, and hence the LVs, you'll have to use devices other than those already listed.

[amsethi]

Hi Patrick
Thanks for the prompt reply.
The disks ranging c13t0d[0-4] and c15t0d[0-4] are alternate path to the same set of LUNs. The data that was there previously was 2GB per physical disk i.e 10GB or 2555 PE(approx.) in total and but in my disk the each physical disk size is 3GB so the total size should be 15GB or 3832 PE.

I am not able to see those extra Physical Extent PE on my new disk instead I am seeing "Alloc PE 2555".

Free PE should 1277 approx.

~Amit

[amsethi]

Patrick
The above issue I am seeing after I changed the volume group to a new set of Physical Disks each of whose size is 3GB as mentioned before.

I am not able to see those free PE's present in my new disks.

~Amit

[Senthil Kumar .A_1]

Hi,

Could you let us know, how you increased the space of 5 physical disk from 2GB to 3GB ?

SK

[freddy_21]

if your disk already configre at lvm, you cant extend the disk.

The solution Add New disk. the size must same with existing or less than existing.

example you have new disk c15t0d4 ( new disk )

thanks
freddy

[freddy_21]

sorry maybe can make misunderstanding.

if the disk already configure at lvm, you cant extend ( resize 2 GB to 3 GB ) disk.


Thanks
Freddy

[Patrick Wallek]

How did you "changed the volume group to a new set of Physical Disks each of whose size is 3GB "? Are these new disks on a different disk array? Or are they on the same array, but you expanded the LUNs?

[amsethi]

I have migrated my data from an older disk to a newer one where the space was more i.e. 3GB for each LUN. But I am able to see only 2 GB space created on each physical disk of that volume group.

I am unable to extend those available space which is invisible to me.

[amsethi]

Patrick

I have migrated the data to a new disks using an internal feature. Those disks are on different set of array disks.

Amit

[amsethi]

Patrick

Even I would like know how to extend the physical volume of a disk which is part of a existing volume group when the LUN size is increased on the storage side .

Amit

[Senthil Kumar .A_1]

Hi,

Can you elaborate on "Internal Feature" a little more please...

As far as increasing the size of the existing lun from storage side is concerned, the answer is the LVM will not identify the new size. You might have to recreate the VG with the Luns to make the LVM realize the actual size of PV. One other issue, while creating a VG, always make sure the first PV added to a VG is the largest among the group of PV's you wish to add. For example, if you have 2 and 3GB disk. If you happen to add 2GB first, the VG when created will calculate the "Number of PE's" per VG and hardlock it. Later when you add the 3 GB disk only 2 Gb of it will be recognized. Meaning you need to trash the VG and recreate it again to rectify the situation. Though the order of PV addition, I'm not too sure. I will wait for experienced Admins to reaffirm my point.

SK

[amsethi]

Sorry Senthil I can't disclose the feature. Hope everybody understands.

But I can tell you one thing that I used all the space of my older physical disks i.e 2GB each and then migrated it to a new set of physical disks each having 3GB size.

[Vivek_Pendse]

there is a limitation in PE for existing vg.
you will need to take backup of existing vg & restore it on new created vg.
while creating vg; mention pe_size more than the existing..
e.g.
# vgcreate -s 16 PV_NAME

Thanks,
Vivek

[amsethi]

Vivek

I did vgcfgbackup and vgcfgrestore but the with "vgcreate -s 16 pv_path" but still the physical disk size does not changed.

Amit

[Senthil Kumar .A_1]

Hi,

What vivek meant was not vgcfgbackup and vgvfgrestore, he meant the backup of data on LV's for the VG, delete the existing VG, recreate them and restore teh data.

Anyway for whats worth it, looks like from HPUX 11iv3(11.31) onwards, there seems to be a command by name "vgmodify" that lets you change the parameters registered in VGRA. I'm not too sure this would remediate your situation. Also a word of mouth, there is an unsupported version of vgmodify for 11.11. May be you can try it.

SK

[KathyL1]

The vgmodify command which is available for HP-UX 11i V2 if you install the LVM patches PHCO_35524 and PHKL_36244.

Refer to the following Technical Knowledge Base document for specific information about the vgmodify command and Max PE per PV - http://www2.itrc.hp.com/service/cki/docDisplay.do?docLocale=en&docId=emr_na-c0
1007548-1


Kathy