How to safely remove EMC cx500 lunes from hpux 11i?

[Bob Brown_1]

I have an RP8400 connected to an EMC CX500 SAN.
We need to remove a bunch of old LUNS and add a few back.

When we first started working with the EMC SAN on hpux we had a problem whereby we added 3 LUNS, removed 1, tried to add a new one and the hpux host didn't see the LUN (didn't create device files etc), no matter what we did we could not make the hpux system see the newly added LUN...

UNTIL: we added the removed LUN back in..then it saw the new lun and added it in fine...

it's almost like it needed the old lun to stay there as a placeholder.

Now that we need to do a bunch of lun moving on several hpux 11i vpar's on this emc san, I am looking for guidance on how to do this safely without running into this 'placeholder' problem.

As to how things are defined, each filesystem on the SAN is in its own logical volume, in its own volume group. (as filesystems have needed to grow, we've added more san luns to the volume group and then just grown the filesystem).

thanks.

-Bob

[Steven E. Protter]

Shalom,

Make sure powerpath if used and required/recommended patches from EMC are installed prior to changes.

Make sure a recent bi-annual patch set is also installed.

Back up all the data in case of a foobar and proceed.

Note there are limitations to how much storage can be in a volume group based on how it was created. The -p (physical volume limit) and -s (size of PE's) can but often is not be used to increase the actual capacity of a volume group.

You may be forced to vgcreate the volume groups involved from scratch.

SEP

[Christian Tremblay]

I'm not sure is this applies to your SAN, but on some LUN 0 is reserved as an "administrative LUN" and should not be used for storage proper.

Was by any chance the LUN you added back LUN 0 ?

That may be your problem..

Chris

[Bob Brown_1]

I don't think it was a LUN0 problem.
the problem is not with volume groups or logical volumes.

The problem is that one the LUN was removed from the host (lv deleted, vg deleted etc and the LUN removed), the new one added back in was NOT seen by powerpath (insf didn't see it, powerpath didn't see etc)...until I added the deleted LUN back in (didn't define it to the system, just added it back in)...then it saw it ok.

-Bob