Can't extend LUN size beyond 2TB using vgmodify

[Dominic Espejo_1]

Extended metaLUN size from 1.5TB to 4.5TB on EMC disk array. To verify new LUN size I use diskinfo:
#diskinfo /dev/rdsk/c10t0d1
SCSI describe of /dev/rdsk/c10t0d1:
vendor: DGC
product id: CX3-20cWDR5
type: direct access
size: 4764241408 Kbytes
bytes per sector: 512

but when I try to extend the volume group using "vgmodify -p 61 -e 65535" I get this error:
Warning: The physical volume "/dev/rdsk/c10t0d1", is initialized
to use only the first 2147483647KB of disk space. Disk space beyond this
point will not be used by LVM.

How do I use the space beyond the 2TB?

[James R. Ferguson]

Hi:

Knowing what release (11.23 or 11.31) and whether or not you have appropriate patches would be helpful. See:

http://docs.hp.com/en/6054/LVM_Limits_White_Paper_V4.pdf

Regards!

...JRF...

[Dominic Espejo_1]

oops, sorry:
#uname -a
HP-UX t7tdb06 B.11.31 U ia64

#swlist|grep -E -i "gold|qpk"
QPKAPPS B.11.31.0809.326 Applications Patches for HP-UX 11i v3, September 2008
QPKBASE B.11.31.0809.326 Base Quality Pack Bundle for HP-UX 11i v3, September 2008

[Andrew Rutter · Accepted solution]

hi,

85535 is the largest number of physical extents allowed. You are reaching this, but you probably have a sml physical extent size.

vgmodify doesnt allow for changing the size of physical extents.

check the extent size with vgdisplay.

you may need to backup the vg, and just start again

Andy

[Dominic Espejo_1]

Thanks, I checked the PE size and it was set to 32 MB so that's why I can only access 2TB of the PV (I'm hitting the 65535 limit). Is there a way to resize the PE without recreating the volume group?

[Bill Hassell]

> ... PE size and it was set to 32 MB so that's why I can only access 2TB of the PV (I'm hitting the 65535 limit). Is there a way to resize the PE without recreating the volume group?

Nope. That's why TB sizes must be planned way ahead. 64MB is barely enough -- I would use 128 MB extents (or 256 MB) to keep the quantity of PEs to a reasonable number (65,000 is a *lot* of extents). The PE_SIZE is the basic building block for managing the VG space. Changing the PE_SIZE requires a completely new space management layout.

[Dominic Espejo_1]

*groan* Now I'll have to do a LUN migration on the EMC array to free up these disks and create a new LUN, but I'll use the parameters as you suggested. Thanks for the advice.

[Dominic Espejo_1]

PE size of 32MB was to small for 4.5TB PV, will create a new VG, increase PE size to 128MB and do a LUN migration.