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Dynamic Lun Expansion on HP-UX 11.31

Doug Wilburn

Dynamic Lun Expansion on HP-UX 11.31

I have an rx2660 running HP-UX11.31 connected to EVA6400. On the EVA, I increased one of my luns (presented to the HP-UX host) from 20GB to 30GB. Then, on the HP-UX host, I ran the command: "ioscan -fnNC disk" but viewing the out put from diskinfo, the OS still sees the disk as a 20GB disk. Is there something else I need to do? 

Acclaimed Contributor

Re: Dynamic Lun Expansion on HP-UX 11.31

You need to use "vgmodify" - see man page.

Hope this helps!

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Steven E. Protter
Exalted Contributor

Re: Dynamic Lun Expansion on HP-UX 11.31



I'm glad you at least can use vgmodify now. I'm going to suggest an pain free alternative to expanding LUN sizes.


Expanding LUN sizes has never been easy with HP-UX and often leads to down time to get the size recognition to work.


Alternate suggestion: When adding disk, build a new LUN on storage, present the LUN to the system.



insf -e -C disk

ioscan -fnCdisk or

ioscan -fnNCdisk


pvcreate the newly discovered disk


vgextend the volume group you want to include the new disk


lvextend to extend the logical volume.


extendfs or fsadm to expand the file system. extendfs requires the file system be umounted. fsadm requires a paid license for Online JFS to work properly.



Steven E Protter
Owner of ISN Corporation
Arunabha Banerjee
Valued Contributor

Re: Dynamic Lun Expansion on HP-UX 11.31

Please have a look of the whitepaper that describes how to do it.

Occasional Visitor

Re: Dynamic Lun Expansion on HP-UX 11.31



only ioscan will not add the disk to the existing vg,


below steps


download evainfo tool.


1.identify the wwwn no from eva gui.

2../evainfo -w wwwnno iosacn -m dsf (cxtydz)   ----  u can find the other path for the links

4.pvcreate persistent device file ( use raw disk ) 

5.vgextend /dev/vgname persistent device file

6.lvextend -L10*1024(as per ur requirement) /dev/vgname/lvname

7.fsadm -F vxfs -b sizeM [mountpoint]    ---  if u have online jfs installed,if not do extendfs but need to unmount the filesystem)

8.check with bdf.


if it is in cluster


Do vgexport -p -s -v -m /tmp/ /dev/vgname


transfer the map file to failover server via ftp,rlogin

in failover


Do vgimport -s -v -N -m /tmp/ /dev/vgname






Arunabha Banerjee
Valued Contributor

Re: Dynamic Lun Expansion on HP-UX 11.31

Hi Madhuchakkaravarthy.A


Your steps are for just adding a new LUN. So it is not the procedure for Dynamic Lun Expansion. Dynamic Lun Expansion is totally a different thing.


When a LUN is dynamically grown, use vgmodify to enable LVM to access this new space. After the
volume group has been adjusted by vgmodify, you can allocate the new space using the normal
LVM method by lvextend or lvcreate.


Please check page no 14 of the Doc which i already provided in my previous post.


In futere please understand the question/query before posting. :smileyhappy:

Valued Contributor

Re: Dynamic Lun Expansion on HP-UX 11.31

1. run ioscan -C disk

2. run vgmodify -t -v on the volume group that has the lun you expanded on the EVA.

3. look at the vgmodify table and choose the mav_pv and max_pe options that will get you to 30GB.

4. run vgmodify -a -p <max_pv> -e <max_pe> -E /dev/vgXX

5. expand the lvol (lvextend).

6. expand the filesystem (fsadm).