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CX3-10c LUN Current Owner and Default Owner
I have set the LUN Default Owner to SP B, but its current owner is still SP A.
How can I make its current owner switched to SP B?
This post is more than 5 years old
77 Posts
0
1090
I have set the LUN Default Owner to SP B, but its current owner is still SP A.
How can I make its current owner switched to SP B?
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sameek
60 Posts
0
October 3rd, 2013 05:00
"Auto assign enables or disables (default) auto assign for a LUN. Auto assign controls the ownership of the LUN when an SP fails in a storage system with two SPs. You enable or disable auto assign for a LUN when you bind it. You can also enable or disable it after the LUN is bound without affecting the data on it.
With auto assign enabled, if the SP that owns the LUN fails and the server tries to access that LUN through the second SP, the second SP assumes ownership of the LUN to enable access. The second SP continues to own the LUN until the failed SP is replaced and the storage system is powered up. Then, ownership of the LUN returns to its default owner. If auto assign is disabled in this situation, the second SP does not assume ownership of the LUN, and access to the LUN does not occur.
If you are running failover software on a server connected to the LUNs in a storage system, you must disable auto assignment for all LUNs that you want the software to fail over when an SP fails. In this situation, the failover software, not auto assign, controls ownership of the LUN in a storage system with two SPs."
Next point - Yes, you can change SP ownership of your LUNs, but (and it is a huge but) if your LUNs are currently presented to a host, you could lose access if you do not have failover software properly running (e.g. PowerPath). Your zoning must also be correct or you may not be able to access the LUNs.
If you right click on a LUN and go to Properties, there are options related to ownership. You can change the default owner of each LUN you want to move, but that will not move the LUNs to the other SP. If you right click a LUN and select Trespass, the LUN will immediately change ownership.
You should do the necessary research to make sure you do not cause DL/DU during your ownership configurations.
Thanks
Sameeksha
kelleg
4.5K Posts
1
October 3rd, 2013 10:00
An additional note. Changing the Default SP Owner for a Raid Group LUN is an acceptable solution for changing which SP Owns a LUN if you need to balance the IO workload between the two SP's. If the LUN is changing (trespassing) the Current SP Owner, that means the host that owns the LUN is pulling the LUN to a different path. But could also mean that more than one host has access to that LUN and each host see's the LUN on different paths. This can lead to a trespass storm, which is not a good thing.
For Pool LUNs, you MUST NEVER change the Default SP owner to be different than the Allocated SP owner. With Pool LUNs you should always have the following order: Current = Default = Allocated. See KB 88169 for more information about this issue.
The Auto Assign and Auto Trespass is only used when the host does not have failover software (and internally for metaLUNs). You should never have these set unless the host does not have failover software (which is NOT a good idea).
glen