It is essential to understand that not all storage arrays are the same, even if they look the same. Here, we are talking about ALUA arrays. Although they have two independent controllers, the interior design is different compared to higher-tier storage. In ALUA arrays, only one service processor (the controller) owns the device (the logical volume). This means that if an I/O request is received by the service processor that owns the device, there is no impact on the performance. On the other hand, if the service processor that does not own the device receives the I/O request, the I/O is first internally forwarded to the service processor that owns the device, and then the actual I/O is processed.