No it doesnt. the auto-assign is for the initial ownership of the LUN when creating them. the system will normally alternate between A & B to balance the amount of lun on each.
If you know you will have 2 lun's that have high IO, you can manually create the first and place it on A and the other on B.
When you are creating abunch of the same size lun's at the same time, it is good to check the Auto button
You can make either SP the owner at anytme by going to properties and changing it. Then you need to trespass that lun over.
When you are in a Properties screen or on the Create screen, if you click on the Help button it will provide you with information about what all the options on that screen are.
For Release 30 - Unisphere
When you create a LUN one of the check boxes on the Advanced tab is called "Enable Auto Assign" This is the Help description:
"Enables or disables Auto-assign for this LUN. Auto-assign applies only to a storage system that has two SPs and a LUN that is not a hot spare."
A more detailed explanation:
Auto assign for a LUN
Important Enable this LUN property only if the connected host does not use failover software. The auto assign property is ignored when the storage system's failover mode for an initiator is set to 1. This property will not interfere with PowerPath's control of a LUN.
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 created 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.
Note The auto assign property is not available for a Hot Spare LUN.
This means that you should not normally check this box unless you do not use failover software on the host (most likely today that is not the case). So if you have PowerPath or PVlink or native MPIO on the host, you would not check this box.
When you select more than one LUN, there is a new section that pops up that allows you to let the array assign the LUN numbers.
kenn2347
3 Apprentice
•
542 Posts
0
December 20th, 2010 08:00
No it doesnt. the auto-assign is for the initial ownership of the LUN when creating them. the system will normally alternate between A & B to balance the amount of lun on each.
If you know you will have 2 lun's that have high IO, you can manually create the first and place it on A and the other on B.
When you are creating abunch of the same size lun's at the same time, it is good to check the Auto button
You can make either SP the owner at anytme by going to properties and changing it. Then you need to trespass that lun over.
kelleg
4 Operator
•
4.5K Posts
0
December 21st, 2010 14:00
When you are in a Properties screen or on the Create screen, if you click on the Help button it will provide you with information about what all the options on that screen are.
For Release 30 - Unisphere
When you create a LUN one of the check boxes on the Advanced tab is called "Enable Auto Assign" This is the Help description:
"Enables or disables Auto-assign for this LUN. Auto-assign applies only to a storage system that has two SPs and a LUN that is not a hot spare."
A more detailed explanation:
Auto assign for a LUN
Important Enable this LUN property only if the connected host does not use failover software. The auto assign property is ignored when the storage system's failover mode for an initiator is set to 1. This property will not interfere with PowerPath's control of a LUN.
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 created 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.
Note The auto assign property is not available for a Hot Spare LUN.
This means that you should not normally check this box unless you do not use failover software on the host (most likely today that is not the case). So if you have PowerPath or PVlink or native MPIO on the host, you would not check this box.
When you select more than one LUN, there is a new section that pops up that allows you to let the array assign the LUN numbers.
glen