EVA 6000 and HP-UX using pvlinks, which disks are which?

[Jeff Almaguer]

If I assign four 10Gb disks to an HP-UX box running pvlinks I'm going to get 4 device files per disk. For 4 disks it will make 16 device files. What if there are already some 10Gb disks on that box? It will get very confusing very fast. Is there any unique identifier per vdisk so I'll know which ones to vgcreate?

Xpinfo shows a unique LDEV number per disk. Is there anything similar for EVA?

If there is anyone using an EVA in a UNIX environment with pvlinks I'd sure like to know how you get around this confusion.

Thanks!

[Ivan Ferreira · Accepted solution]

See this thread, you will get more than one answer here:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=970450

[Vincent Fleming]

First off, you should zone your switches such that the LUNs are seen on a single port - that way you get only 2 copies of the LUN.

Second, use the hardware path from ioscan to get identify the devices. There are many descriptions of how to decode hardware paths in these forums - so if you need help with that, just search.

Good luck,

Vince

[Jeff Almaguer]

Thank you Ivan and Vincent. Because I am using pvlinks only, not Secure Path, it looks as though the only way I will be able to positively identify the EVA vdisks will be by deciphering the hardware paths. If there is another solution please reply.

[krusty]

Jeff,

See my response in this thread:

http://forums1.itrc.hp.com/service/forums/questionanswer.do?threadId=947298

I think it will answer your question on this issue.


Cheers,

Curt

[Jeff Almaguer]

Curt, I'm not using Secure Path therefore the 'spmgr' command is not available.

[Pat Obrien_1]

Vincent,
Your recommendation is not my interpretation of the eva xl best practises. I figure it would suffice in a low throughput environment, but I will use between 4-8 hba's, and expect 800-900 MB/s from an eva XL. I already have sp on these hosts with eva5k active-passive, though I do know i will have to re-install to get the autopath component of sp, and so I expect to use HPUX multipath to the preferred controller, and then configure redundant pvlink paths. However as Jeff alluded to, its all in the devices files. So far I clearly understand to have the domain ids of the dual fabric switches different as this will help identify hba and path to the disk. And then I figure I am going to get real good at hardware paths to identify luns.

[Jeff Almaguer]

"And then I figure I am going to get real good at hardware paths to identify luns."

-Pat Obrien

Precisely Pat. You hit the nail squarely on the head. After posting my question to the ITRC, thoroughly questioning the HP CE that installed our EVA and opening a ticket with HP technical support I've come to the same conclusion. Those of us using pvlinks (and only pvlinks, stop it with the 'spmgr' already) will have to become pros at deciphering hardware paths. It's crude but it's all we've got. There is an excellent tutorial at the link below.

http://docs.hp.com/en/A6795-90006/ch01s11.html

[Uwe Zessin]

And Figure 1-4 shows why it is not a good idea to use Domain ID 8 on a Fibre Channel switch: the value is used to indicate a private loop.

[Pat Obrien_1]

What I forgot to say was I have between 100 and 240 luns per eva. I have 7 distinct sans, and some have 5 eva, and some hosts have 8 hba's. I figurr to be the master of ids, though it comes back to the hardware path components, hba, switch, and lun number. I believe the lun number is maintained across all hba's.