Logical Drive Not On Preferred Path
What Caused the Problem?
There is a problem accessing the controller listed in the Recovery Guru Details Area. Any logical drives that have this controller assigned as their preferred path will be moved to the non-preferred path (alternate controller). This procedure will help you pinpoint the problem along the data path. Because the logical drives will be moved to the alternate controller, they should still be accessible. Therefore, no action is required on the individual logical drives.


Possible causes include:

The controller failed a manually initiated diagnostic test and was placed Offline.
The controller was manually placed Offline using the Advanced >> Recovery >> Place Controller >> Offline menu option.
There are disconnected or faulty cables.
A Hub or Fabric switch is not functioning properly.
A host adapter has failed.
The storage subsystem contains a defective RAID controller.

查链路，有条链路不通了。

这个错太常见了，上面解释可能的原因也解释得很清楚

Just drop by and find this thread...

原链路不通导致LUN切换到另一条链路，可以先确认故障链路上的设备（HBA,光纤线，switch sfp模块），正常后最好用多余空间先建个小lun到原故障链路controler，不发生切换可确认没问题，将切换的lun切回到Preferred Path