Re: ASM and EMC PowerPath

  • From: "Radoulov, Dimitre" <cichomitiko@xxxxxxxxx>
  • To: Karl Arao <karlarao@xxxxxxxxx>
  • Date: Sun, 10 Apr 2011 19:47:46 +0200


Hi Karl,
yes, I understand that asmlib will work with any valid path to the disks,
but in order to actually use the multipath, you need to configure it correctly (check MOS Note 394956.1).
You seem to have the default configuration (no scanorder and/or scanexclude), if on reboot (or after scandisk) asmlib chooses a path different than the multipath and the chosen path becomes unavailable, you won't be able to access those disks 
no more (you'll get errors).
If you configure the access to the disks with asmlib (via scanorder or scanexclude) through the multipath, the disks will remain accessible even if you loose one or more 
of the paths to those disks (assuming at least one path is still available).



Best regards
Dimitre

On 10/04/2011 15:19, Karl Arao wrote:


Hi Dimitre,

The major/minor of emcpowerp1 is 120  241...
I would do this report every time there will be change on the storage side (let's say SAN Migration, powerpath upgrade)
But take note, ASM is not really dependent on the major/minor numbers.. it is dependent on the ASM header information when you created that ASM disk.
So let's say I'll be migrating to a new SAN storage.. I can do a SAN copy on a different set of LUNs on that new SAN and have totally new major/minor numbers but when you boot again the server with the new LUNs the ASM will still work as if nothing happened (no partprobe and scandisks needed). Cool right? :)
BTW, we did no changes (default) on the ORACLEASM_SCANORDER and ORACLEASM_SCANEXCLUDE 


--
Karl Arao
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