PowerPath and PVlinks.

[Steve Post]

Scott, I looked at that procedure generation. THAT works. My problem with the powerlink website is not logging in. It's getting kicked out every 5 minutes. It's kinda annoying! But once I'm at that generator, it seems to work fine. My EMC woes here are just about about non-critical information. If I had a real problem, they usually call me about 5 minutes before the hpux hardware even pages me.

And Christian, thank you for your replies. Even though you use a different version of disk array, I WANTED to know why there were differing opinions on this subject. I didn't like the idea of doing X simply because everyone does it.

thanks.
steve

[Steve Pittenger]

Steve,

Not that this is directly answering your issue but I thought was noteworthy because I am currently working a case with HP and EMC on this. We use PVLinks in our Clariion environment and have for years with great success. After applying patches recently to HP-UX 11.11, we started experiencing excessive lun trespasses in our Clariion logs related to the HP-UX hosts. EMC has a Primus solution (emc143405) that identifies the patch that caused the problem as a LVM patch PHKL_34518. The morale of a long and still being investigated story is that the official HP statement is that they do not support PVLinks in a Clariion environment. Furthermore, once I opened a case with HP they have so far stated there is no plan to remove the code from LVM that is causing this trespass issue. The funny part is that EMC says they do support PVLinks in this type of environment and as stated above has worked well for use for the past 5 years. Currently, I am awaiting the two companies to let me know the outcome. My options as presented to me from both companies are to remove the alternate links from my volume groups (PVLinks), install EMC's Powerpath on these hosts, or back out the LVM patch that caused this problem. The first option is no good unless you perform the second at the same time unless you want to be exposed to a path failure. The third option is not good if you want to keep your LVM code fairly current since there are no plans to remove the code causing the issue. Sounds like you are on the right track with Powerpath as your selection based on what I am hearing currently. As a previous respondent mentioned, just follow the EMC procedure generator for your situation and you should be fine. Good luck.

Steve

[sathish kannan]

Steve Post,
Sorry for taking your question away. I just want to get clarification from Steve Pittenger

Steve Pittenger,
I am not aware of HP or EMC statement about the non support of PV links on CLARiiON. do you have any documentes or link and could you please post us.

I know that HP patch causes a trespass ping-pong with failovermode=1 and EMC recommed to remove those patches.


Regards
Sathish

[Scott Riley]

I would find it really disturbing, if it's confirmed, that HP would not support Clariion in a PV Links environment, and I would ask for some documentation or a written statement confirming that. Pulling the plug on that support would mean pulling the plug on a 15+ year support relationship.

The original PV Links code was written around the time HP was selling the Nike 10 and Nike 20 arrays back in the early 90's. Those were Pre-EMC merger Data General Clariion arrays, and PV Links has supported Clariion arrays ever since.

Perhaps HP is stating they support PowerPath instead of PV Links?

By the way, there is a "free" version of PowerPath available, for the Clariion only, that duplicates PV Link capabilities without the more advanced load balancing that the purchased license gives you.

[Steve Pittenger]

Sathish,
Here is the link HP support provided me that talks about PVLink support. Footnote #4 is the particular note and it's explanation is about halfway down the document. Don't make the mistake I did and look at the footnote at the bottom of the document as that pertains to a different section of the document.
http://www.hp.com/products1/serverconnectivity/mass_storage_devices.html

I use failovermode=0 in all my PVLinks implementations and never had this trespassing issue until I applied the patch I listed in my above posting. That is what caused me to start researching with both companies and am still waiting for a final answer even though the above website(HP) states that it is not supported.

Scott,

I agree with you on the really disturbing part and that is why I continue to have the two companies speak about it. I am also, until recently, a very satisfied PVLinks customer in a Clariion environment. You are correct about the free Powerpath (which I believe they refer to as Powerpath Lite) and this seems to be the way both companies want customers to head. If this thread is still open when I get a definitive answer from both companies, I will post it here.

[Steve Post]

I have no problem keeping this thread open forever.

[Scott Riley]

Steve,

I checked the EMC support matrix, and it looks like PV Links is no longer supported for Clariion (at least the CX-300), it's not showing up as a supported solution. It looks like HP and EMC are both backing PowerPath...

- Scott

[Cesare Salvioni]

just to add that recently i experienced slow performances with hpux with pvlinks and cx300.
Problem is lot of trespass caused on the storage by a new feature of pvlink: proactive polling.
Good news is that you can disable this feature with pvchange -n on all the pvlink (primary and alternate). This way the trespass should be reduced only to the check at vg activation and in case of failure.
Hope it helps

[Cesare Salvioni]

oppss wrong command, right one is:
pvchange -p n