CA-EVA & HP-UX Volume expansion.

[ALCS]

Hi,

We have the need to increase an HP-UX Volume which is a source vdisk within a CA-EVA DR group.

I beleive we have two options:
option 1 is to backup the vdisk, increase its disk space from CVEVA, then recreate the volume to detect the increased capacity then restore, in this way the DR vdisk will be updated.

option 2 is to create a new vdisk2 place it in the same DR group (CA will then create a second vdisk2 at the destination)then add the capacity to the original volume from Unix side but here comes the question: what happens if we do failover?
will the two destination vdisks (initial vdisk & vdisk2) successfully form the expanded volume?

Appreciate responses.

Farid

[Amar_Joshi]

If you are using ASYNC CA replication then it's better if you do NOT use the LVM to join the group because with EVA you have the option to expand the VDISK and then LVEXTEND/EXTENDFS to expand the LVOL. Recreating the new relationship in DR group should not be painful if you have a good bandwidth between 2 EVAs.

With ASYNC CA, in case of abrupt shutdown of primary EVA one can not assure that all the PVs used for a VG are in the consistent state and may fail to mount the LVOL at remote end. But with SYNC you won't have that problem. But overall management will become easy if you expand the existing mounts.

[IBaltay]

Hi,
for HP-UX 11iv2 with PHCO_35524, 11iv3 there is a new command for the volume group dynamic LUN expansion - vgmodify.
1. the older ITRC on this is http://forums12.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1213331293137+28353475&threadId=832370
2. the newer and more relevant is the following article:
http://forums12.itrc.hp.com/service/forums/questionanswer.do?admit=109447627+1213331389046+28353475&threadId=1207313
Resume:
the correct sequence of usage vgmodify in its 3 modes sequentialy:
table mode ->-t table of possible settings
review mode ->-r rewiev if the new settings
based upon the other arguments can be successfuly applied
change mode ->new settings are applied to the VG
The mechanism:
after the LUN dynamic change, vgmodify should be used to allow LVM to access the new space. After the VG vgmodify adjustment the new space can be allocated with normal LVM commands lvextend/lvcreate

[IBaltay]

Hi,
I am sending you also the LVM vgmodify document link:
http://h20000.www2.hp.com/bc/docs/support/SupportManual/c01920387/c01920387.pdf (BSC link updated by admin)

[IBaltay]

Hi,
The safiest CA DR vdisk expansion can be found here:
http://forums12.itrc.hp.com/service/forums/questionanswer.do?threadId=1240508

[ALCS]

Thank you for yout reply
We have HP-UX v1 so the dynamic lun increase is not available.
However if we extend the same LUN from the EVA side (i.e increase the space of the vdisk from Command View)
Then we noticed that the Physical Volume size will be increased (diskinfo) BUT its corresponding VG will not recognise the new size so we cannot use lvextend..

appreciate your reply.

Farid

[Torsten.]

As you already know the LVM in 11.11 cannot handle increasing disk devices.
So your option is re-creating the VG.