Alternate multi-pathing

[ae_jenkins]

I can't seem to be able to do this with the cmdlets, and my .NET namespace skill stink, so . . .

Trying to figure out a script that can take a mult-path SAN connection, and have it alternate which HBA is active for consecutive LUNs.

For example (am excluding vmhba0 on purpose):

vmhba1:0:1

vmhba2:0:2

vmhba1:0:3

vmhba2:0:4

Thanks so much - please reply if my request isn't clear.

[LucD]

Carter wrote a nice article about this on his blog.

See Managing storage paths with PowerShell.

[ae_jenkins]

Thanks LucD - it does provide more information than what I had, but since my scripting & API skills are pretty lame, I need further help trying to not necessarily changing the policy (fixed vs RR, for example) but instead changing the "Preferred" flag in the "Change Path State" properties.

Thanks!

[LucD]

If you look at the HostMultipathInfoFixedLogicalUnitPolicy object, which is an extension of the HostMultipathInfoLogicalUnitPolicy object, you will notice that it contains a property prefer where you can enter the preferred path.

To use the preferred path you have in any case to set the policy to fixed.

So the 2nd code sample in Carter's article is what you need.

Looping through all the LUNs and keeping track of the paths and which one to use should be straightforward.

If not let us know exactly what you want to do (number of LUNs, number of paths, does each LUN have the same paths...)

[ae_jenkins]

LucD - thanks. I had to "visually parse" the article some more before I could understand it. That got it.

AEJ

[justin_emerson]

ae_jenkins:

Were you able to get this kind of script working? I'm looking at doing the same kind of thing, basically replicating what this PERL script does but on a cluster-wide basis:

http://www.yellow-bricks.com/2008/04/01/load-balancing-activeactive-sans/

If you did get it to work, would you mind posting it?