Load Balancing Logical Units in an Active/Passive Storage System

Abstract

An approach is provided in which a storage system includes a first storage controller, a second storage controller, and multiple logical units. The storage system determines that a controller traffic load ratio between the first storage controller and the second storage controller has reached a threshold. In turn, the storage system selects one of the logical units and changes a preferred controller ownership of the selected logical unit from the first storage controller to the second storage controller to balance the controller traffic load ratio.

1 . A method comprising:
 determining, by a storage system, that a controller traffic load ratio between a first storage controller and a second storage controller has reached a threshold, wherein the first storage controller and the second storage controller correspond to at least one of a plurality of logical units included in the storage system;   selecting, by the storage system, one of the plurality of logical units; and   changing, by the storage system, a preferred controller ownership corresponding to the selected logical unit from the first storage controller to the second storage controller in response to the determination.   
     
     
         2 . The method of  claim 1  wherein the storage system configures the first storage controller and the second storage controller in an active/passive controller configuration. 
     
     
         3 . The method of  claim 1  wherein, prior to the determination that the controller traffic load ratio has reached the threshold, the method further comprises:
 identifying a first data traffic amount passing through the first storage controller corresponding to one or more first logical units included in the plurality of logical units and; 
 identifying a second data traffic amount passing through the second storage controller corresponding to one or more second logical units included in the plurality of logical units; and 
 computing the controller traffic load ratio based upon the first data traffic amount and the second data traffic amount. 
 
     
     
         4 . The method of  claim 1  further comprising:
 subsequent to changing the preferred controller ownership, receiving an ownership inquiry from a host system, the ownership inquiry including a logical unit identifier corresponding to the selected logical unit; and 
 sending an ownership response to the host system, wherein the ownership response includes a preferred controller identifier corresponding to the second storage controller. 
 
     
     
         5 . The method of  claim 1  further comprising:
 displaying, by the storage system, an ownership configuration window to a user; 
 receiving an ownership configuration selection from the user; 
 determining that the ownership configuration selection is a dynamic ownership selection; and 
 configuring the storage system to balance the controller traffic load ratio, wherein the balancing includes changing one or more preferred controller ownerships of one or more of the plurality of logical units when the controller traffic load ratio reaches the threshold. 
 
     
     
         6 . The method of  claim 6  wherein the threshold is an auto-balance threshold received from the user. 
     
     
         7 . The method of  claim 1  wherein each of the plurality of logical units corresponds to at least a portion of a physical storage device.