AIX hdisk numbering 1

[phorbiuz]

Hi

We have an AIX 5.1 server connected to a HDS SAN using dual pathing over 2 HBA's.

We had a problem last week where we lost one feed. I found it was a cable problem but I wasn't on-site for the resolution. The techie who completed the resolution is not in this week.

Hdisk0 and 1 are internal disks assigned to the rootvg. Hdisk14 and 15 are internal assigned to an appsvg.

Now for the HDS 'issue'. Whatever work was completed last week now has our remaining disks re-numbered as if it has seen them from new. As its HDS and each disk is dual-pathed we use the HDLM drivers.

For the 7 HDS luns we have an lspv listing of dlmfdrv0 - 7 (which is the actual devices we use). The lspv listing also shows the 14 hdisk devices (although they are correctly not listed as active).

Our numbering system used to be hdisk2 - 8 for one path, with 16 - 22 for the second path. Now its a straight 18 - 31.

Q. Can I do an rmdev on the hdisks to renumber them back to our documentation without actually affecting the dlmfdrv devices?

Thanks in advance.

 

[DukeSSD]

In theory, yes.
AIX does not care what the disks are called, it only uses the disk PVID, changing the hdisk numbers will not affect the PVID or AIX.
AIX uses the ODM to translate the PVID in to a hdisk number just to make them easier for us humans to relate to.
I say in theory because I do not know if the HDLM driver works the same way as AIX, you might have issues with your dlmfdrv devices if they are mapped from the hdisk numbers rather than the PVID of the disks, if you change the hdisk to PVID relation what will the HDLM driver make of it?
The fact it was all working when you got back suggests the dlmfdrv devices are also configured from the PVID, either that or they did a lot of recovery work whilst you were away.
From the disk numbers it seems they have been moved about over time, where did hdisk9 to 13 go?
This could cause you hassle reconfiguring the disks back to their original numbers (with hdisk9 to 13 missing).
Would it be easier to update the documentation?