topic Re: Changing WWN in HPE EVA Storage

Changing WWN

Filipe_1 — Thu, 21 Jul 2005 06:40:59 GMT

Hi folks,

Is there any way to change a WWN of an HBA?

Thanks! Plenty of points to assign.

Filipe.

Re: Changing WWN

Rainer von Bongartz — Thu, 21 Jul 2005 06:47:55 GMT

No, you can't do that.

To be a World Wide Name, a WWN must be unique and set by the manufacturer of the card.

Just the same as a MAC Address for a LAN adapter

Regards
Rainer

Re: Changing WWN

Simon Hargrave — Thu, 21 Jul 2005 06:49:51 GMT

I believe the WWN is hardcoded to the card at manufacture.

What reason would you have to change this?

Re: Changing WWN

Filipe_1 — Thu, 21 Jul 2005 06:57:19 GMT

> To be a World Wide Name, a WWN must be unique and set by the manufacturer of the card.

As a matter of fact you can use the same argument with MAC addresses, and it is perfectly reasonable. But you can do that with most NIC brands...

And I know that some HBAs used on other platforms (jaycor, for example) you could do that.

Well, the reason is quite simple: we have to "swap" the hardware from two servers. We are planning to use the make recovery from one server to install the other, and if we could preserve the WWN it would save us from lots of storage configuration. In this case, keeping the procedure simple is a big issue.

Thanks anyway for the response!

Re: Changing WWN

Jeff Schussele — Thu, 21 Jul 2005 06:57:44 GMT

I don't believe there's a way to do that like a MAC in /etc/rc.confg.d/netconf.

My 2 cents,
Jeff

Re: Changing WWN

Juan M Leon — Thu, 21 Jul 2005 07:08:55 GMT

Check this thread
http://forums2.itrc.hp.com/service/forums/questionanswer.do?threadId=856758

hope it helps

Re: Changing WWN

marie-noelle jeanson_1 — Thu, 21 Jul 2005 13:22:31 GMT

Filipe,

Which hardware are you swapping? If you keep the same HBAs to move them from one server to the other, the WWN will not change, right?

Marie

Re: Changing WWN

Filipe_1 — Thu, 21 Jul 2005 13:39:57 GMT

Hi Marie,

We are swapping a L3000 for a N4000. The Idea is not physically moving HBAs between servers and also not reconfiguring the storage infra.
Can you foresee any issues?

Thanks!

Re: Changing WWN

Devesh Pant_1 — Thu, 21 Jul 2005 14:29:55 GMT

Filipe
zoning on the SAN switches will have to be redone. Since you re not moving the HBAs, the WWNs will change and as a result you will have to do this.

thanks
DP

Re: Changing WWN

Manoj_36 — Thu, 21 Jul 2005 15:52:46 GMT

Hi,
You can not change the wwn of a HBA, it is unique for each adapter hence not to be changed.
Regards.

Re: Changing WWN

Fabio Ettore — Thu, 21 Jul 2005 15:58:18 GMT

Hi,

a few days ago I saw the following message in a system:

Jul 19 08:41:58 vmunix: 1/0/2/1/0: 'World-wide name' (unique identifier) for device at nport ID 0x6f0002 has
Jul 19 08:41:58 vmunix: changed. If the device has been replaced intentionally, please use the
Jul 19 08:41:58 vmunix: fcmsutil(1M) command's replace_dsk option to allow the new device to be used.
Jul 19 08:41:58 vmunix: 1/0/2/1/0: Fibre Channel Driver detected a parse error in the FLOGI/PLOGI response
Jul 19 08:41:58 vmunix: returned by nport ID 0x6f0002. FLOGI/PLOGI Fail Code = 0x6.

Then I don't think you can change it manually except if something changes in HBA. In this instance upgrade/reset of a firmware caused that error.

Best regards,
Fabio

Re: Changing WWN

Devesh Pant_1 — Thu, 21 Jul 2005 16:11:47 GMT

Manoj,please see that Filipe clearly states they are swapping a L3000 for a N4000 and the HBAs are not physically moving which to me means, the old ones are going with the old server and the new ones are coming with the new server, as a result the WWNs of the new server will have to be used in the zoning on the SAN switches
thanks
Devesh

Re: Changing WWN

marie-noelle jeanson_1 — Thu, 21 Jul 2005 16:51:25 GMT

Fabio,

There is a simple way to remove the errors you saw in the log file, it is to use the fcmsutil replace_dsk command. FC sees that some disks have changed (WWN has canged), so it issues a warning and does not authorize IO transfer until the sys admin confirms the new disk to use via the fcmsutil replace_dsk command.

See the Fibre Channel Support guide, "Device replacement" (of course, the "without reboot" here does not apply, but the idea is the same.

Marie

Re: Changing WWN

Fabio Ettore — Sun, 24 Jul 2005 10:57:57 GMT

Hi Marie,

I was not so exact when I posted because I didn't write the final solution.
fcmsutil replace_dsk... was launched to solve a piece of the our problem, though it didn't solve completely it. In that case we had many disks in NO_HW status due to the WWN changed and a reboot, magically! :-), solved them.

Best regards,
Fabio

Re: Changing WWN

Stuart Abramson — Sun, 24 Jul 2005 14:34:08 GMT

EMC Control Center has an option to replace one WWWN with another just to address the case of replacing an HBA in machine...