hdisk numbering oddity

[dvsweden]

I have an odd issue. I have a p550 running 5.3 I have it lpared with a vio server and 4 clients. On my dbserver I attached a san and 3 vdisks. I created a vg, lv and fs for eaach san vdisk.

After I mounted the last file system and repbooted the hdisk numbering changed.

I had hdisk 0,1,2,3,4 (1) is a management slice for the san.

2,3,4 are the vdisks for which I created a sanvg1,2,3 sanlv1,2,3 and san1,2,3 file system.

After mounting the last fs and rebooting my hdisk number changed to:
0,1,5,6,7

However, when I do a lshsv (driver installed san utility) I see:
hdisk1,2,3,4

The file systems mount and I am able to do write a test file to each. lspv -p hdisk5,6,7 shows the correct vg,lv and mount point so I am really confused as to what is going on.

I have rebooted now 3 times to make sure the pattern is consistent and it is indeed consistent.

I should mention that this lpar is a nim client if that makes any difference as well.

Any ideas?
Cheers,
David

 

[RodKnowlton]

I can't tell you why your hdisk numbers jumped, but I can tell you not to worry about it.

Volume groups know their physical volumes by the PVID written in their boot record, not their hdisk numbers.

<huge simplification>
At boot, the ODM is updated with any hardware changes found. This would be where your numbers changed.

Hdisks that already have a PVID in their boot record retain that PVID, no matter what device number they may be assigned, so when volume group configuration is performed, the correct disks are assigned to the volume groups.
</huge simplification>

Rod Knowlton
IBM Certified Advanced Technical Expert pSeries and AIX 5L
CompTIA Linux+
CompTIA Security+

 

[dvsweden]

Thank you very much for the response. I did call IBM and they didn't seem worried about it either so I feel a bit better now. Much appreciated.
David