Changing LUN ID for a RDM??

[Garrethh]

Hi All,

Got an interesting issue I'm trying to resolve.

3 ESX 3i servers all happily running and generally have no

issues. The most recent addition however has picked up the LUN's is a

differing order to the existing servers - this doesn't appear to be an

issue for anything other than RDM's.

I have one server which unfortunately is one of the most

critical and I can't migrate it due to the LUN "Not being available to

this host"

All hosts have access to all LUN's - the LUN is available in the HBA paths, the only difference is the LUN ID.

Has anyone seen this before, does anyone have any thoughts on how to

change the LUN ID? I have done the usual Goolging and so far haven't

found much at all.

I have attached pics of the configurations to show the difference, LUN is question is highlighted

Any help, ideas, thoughts - please let me know. Short of powering down and removing/readding the LUN to the host and see if the host picks it up on a different ID.

Cheers,

Garreth.

[AndreTheGiant]

Has anyone seen this before, does anyone have any thoughts on how to change the LUN ID?

There isn't a way cause it doesn't matter.

ESX works with disk UUID not with LUN ID.

The only way to have same LUN ID is add a single LUN (using storage masking), do rescan to all ESX, add the second LUN, do rescan, ...

Andre

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[Garrethh]

Thank Andre.

I know that ESX shouldn't care - when I attempt to do a migration i get the error in the screen shot. Had to black out bits and pieces....

All hosts can see the LUN(s), all host can access the LUN(s) - so why won't it migrate?

Moving from the first host in the VM cluster to the highlighted host.

Garreth.

[AndreTheGiant]

(I think you are trying to use VMotion) are you able to do a cold migration?

RDM is in virtual or physinca mode?

Andre

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[Garrethh]

Yes I am - that's the general point, no server downtime. Sorry if migrating and vmotiondon't REALLY sit in the same class.

I have Vmotioned this server in the past no drama's with no issues - not to mention other servers with RDM's

It's in physical mode for the RDM mapping.

I shouldn't have to do a cold migration - I know that will work as I have done it before. The LUN needs to be removed before doing a cold migration otherwise ESX tries to copy the whole RDM to a VMFS volume on the sam SAN datastore.

I have just Vmotioned a different server with a RDM - no problem, straight across...the only difference is the LUN ID is the same across all servers.

I can confirm I have a second VM withthe exact same issue -the two hosts that have the LUN ID the same can be Vmotioned - the third with the different LUN ID for the same LUN does not allow migration.

Some backgroud on the setup:

3 host in the cluster - full HA, DRS. All hosts have the same SAN connections, all running 3i U4. I can Vmotionall other 38 servers without an issue.

Does that help or hinder? ?:|

Cheers,

Garreth

[AndreTheGiant]

It's in physical mode for the RDM mapping.

This is the problem. I think that you cannot do VMotion on VM with a physical RDM.

To be sure that there isn't a problem with the LUN ID, try a cold migration from one host to another.

If you keep the file position you will not loose your RDM.

Andre

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[Garrethh]

Clearly you didn't read my previous post - I have other VM's with RDM's and those are in physical mode, Vmotions without issue.

It is purely Vmotioning to this one particular host where the LUN ID's differ.

Thanks,

[AndreTheGiant]

It is purely Vmotioning to this one particular host where the LUN ID's differ.

But have you tried to do a cold migration of this VM?

I do no know of LUN mismatch issue, and if cold migration between host does work, then the different LUN ID is not the problem.

Andre

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[Garrethh]

Just an update on this.... I have had to move the VM while powered down, which was not an issue as the RDM LUN was removed from the configuration at the time.

Since being live on the other server I have been able to successfully Vmotion to the third server in the farm which also has the SAME LUN ID for the RDM LUN in question. I am NOT able to Vmotion to the server which has a different LUN ID for the RDM LUN.

Clearly there is some kind of dependancy or condition the host requires where RDM and LUN ID's are in play.

Thanks,

[AndreTheGiant]

I unterstand your problem.

I never notice cause I alway have the same ID, adding one LUN each time.

And I do not know how manually change the ESX LUN ID.

Andre