EMC Clariion array - using powerpath vs pvlinks

I think I've found the answer to whether or not we should use Pvlinks when configuring our volume groups in HP-UX - the answer being no.  It's only recommended to use alternate links when booting from a storage array, which we don't do on any of our HPUX hosts.

From the powerpath admin guide:

EMC recommends using LVM alternate links (PVLinks) when you
boot from a storage system. If the primary path fails, an automatic
switch to the alternate path occurs. If PowerPath is not installed,
using alternate links increases availability in the event of hardware
PowerPath uses alternate links as part of its boot/root failover
strategy, but not for load balancing, path prioritization, or other
PowerPath-related reasons. Thus, EMC recommends that you use
LVM alternate links when booting from a storage system. Otherwise,
EMC recommends disabling PVLinks when using PowerPath.


powerpath check force: "Cannot remove device that is in use"

removing some ports on a clariion on a HP-UX host running service guard, I received the following:
$ powermt check force
Warning: CLARiiON device path c13t2d3 is currently dead.
Cannot remove device that is in use: c13t2d3

Powerpath is pretty darn smart; the last port 0 linked to a disk device was part of the same lvm volume group as one of my cluster lock disks.  It wasn't even listed in as the lock disk for my cluster (in the cluster ascii file), but it was in the same volume group that the lock disk was in.

I had to stop the cluster services on the node, then powerpath allowed me to remove the connection.  This node of the cluster is currently the failover node, so I was able to bring er down without any impact.

HP codewords

codewords used for optional additional pay software in  HP-UX are stored  here in the following format:



#CD_part_number Customer_Id IdType Codeword

manuall set speed and duplex during ignite

set speed and duplex for ignite, instead of relaying on auto-Negotiation: