topic Re: Extend luns in Operating System - HP-UX

Extend luns

Cecile Rosset — Tue, 17 Apr 2007 10:38:31 GMT

I'm new to HPUX. I have a VxFS file system created on a lun as follows:
/env VxFS /dev/dsk/c8t1d0

The above lun is currently 25GB but needs to be extended to 75GB.

# bdf
/dev/dsk/c8t1d0 26214400 1058528 24793468 4% /env

How do I extend the above lun/file system without damaging the data?

Thank you.
Cecile

Re: Extend luns

Steven E. Protter — Tue, 17 Apr 2007 10:44:27 GMT

Shalom,

It depends on a few factors.

To be safe, you MUST back up the data before proceeding.

After extension reboot the system.

See if at that point its possible to lvextend the logical volume to a larger size.

More often than not, you can't and you must destroy the data and rebuild from scratch.

At this size it often also happens that the volume group does not have enough extents to handle the increased size and it must be rebuilt with larger extent size -s or less physical volumes -p (in vgccreate).

Sometimes its eaiser to have the LUN admin copy the lun to a new lun an present that to the system. The filesystem or data should not be mounted or active during the copy.

SEP

Re: Extend luns

Torsten. — Tue, 17 Apr 2007 10:45:30 GMT

Where is the LUN located? An EVA?

Extending the filesystem is not a problem, but it could be a problem to extend the physical volume from the volume manager point of view.

AFAIK the VxVM can do this, but the LVM up to HP-UX 11.23 cannot.

LVM in 11.31 can.

Workarounds:
delete the VG configuration on the LUN and re-create
or
don't expand the LUN but create a new LUN and extend the VG. Doing this you can grow the LVOL without problems.

Re: Extend luns

Armin Kunaschik — Wed, 18 Apr 2007 03:47:32 GMT

To clarify Torstens statement:

VxVM 4.1 supports LUN resizing with "vxdisk resize cXtYdz".
LVM on 11.11/11.23 does not support LUN resizing.

I have not heard about that feature in 11.31... how is it done?

Armin

Re: Extend luns

Torsten. — Wed, 18 Apr 2007 04:11:04 GMT

Regarding 11.31:

"The detection of physical volume size changes (LUN size expansion or contraction) is automatic"

see man vgmodify

http://docs.hp.com/en/B2355-60130/vgmodify.1M.html