HP-UX

Hi,

I am very new to HP-UX, and we're going to be doing a SAN migration.

We're going to take down the machine, and zone it to the new SAN.

My question is, will the device names change and will that interfere with the LVM?

If the new disks come in with different device names, how would I remediate that issue so the LVM would know what disks to point to?

Thanks!

Is the HPUX in question v2 or v3 ?

If the answer is v3, the operation can be online, since on v3, every lun has a WWID.
Just do it port by port, rescan and check paths after each, should not be any issues.

If you want to do it offline, do a vgexport preview (to a file not actual export) of all volume groups on the system using SAN disks (just to be safe do it anyway in each scenario) and deactivate the volume group.

Since the VG info is actually written on disks, even if everything changes (disk names etc.) you will be able to import the volume group using a file you created earlier. There are also other methods (vgscan), but this one is most trivial.

Commands you will require are
scsimgr -> to check lunmap and paths before and after.
ioscan -> to rescan after port change.

This assumes you are using hpux native multipath, not other multipath solutions.

I think it's version 2? Does that make sense? I'm almost sure I am giving the correct output below.

Code:

# uname -r
B.11.23
# swlist -l bundle QPKBASE
# Initializing...
# Contacting target "hostname"...
#
# Target:  hostname:/
#

  QPKBASE       B.11.23.1012.086a Base Quality Pack Bundle for HP-UX 11i v2, December 2010

With HPUX v2, it is a bit tricker to do it online, since for every path you will have one disk device which you have to configure. Agile naming and lun map are on HPUX v3 which makes things considerably easier.

But since you have downtime, export the volume group(s) in which FC disks are into a file (-p -m -s easy to remember )

Stop the service in question and umount the filesystems.
Deactivate and export the volume group.
Unpresent the existing FC luns from host.
Clean up the old device files, you will need to remove the "NO_HW" devices with rmsf -H # this is optional but desirable.
Zone the storage and host on the new switch, and present the luns to the host.
Import the volume group using file you created in setup one.
Activate the volume group and mount filesystems, since you used -m option, it will import with VGID from file.

IF you are migrating SAN root volume group (vg00) additional steps are required.

For online migration, you will need to

Disconnect one path and connect it to a new switch which is zoned and setuped for the host.
Present the luns over that path to host.
Using vgextend, extend the volume group with new luns.
Using vgreduce, remove the existing lun (old switch path)
Disconnect other path, connect to new switch, present, vgextend new, vgreduce old disk path.

Hope that helps.
Regards
Peasant.