Your storage array needs to be configured based on what VMware recommends/supports. The steps below will go through the process of validating that your storage array Multipathing MEM (MPM) is configured according to VMware’s recommendations.
1) Open the VI Client and navigate to an ESXi host > Configuration > Storage > Right click on a datastore, click on Properties > Manage Paths:
By default, the “Storage Array Type” shown above is automatically pulled down from the SAN when you scan for datastores.
2) Once you know the Storage Array Type, go to the VMware Hardware Compatibility List to verify what the recommended configuration is. In this example, we are validating an EMC VNX 5500:
Search for results, and click on the storage array that you are validating:
Notice that the “SATP Plugin” column recommends a different SATP configuration than what we have shown above (VMW_SATP_CX vs. VMW_SATP_ALUA_CX).
To fix this, you need to reconfigure the storage array to go from Failover Level 1 to Failover Level 4 (ALUA). This can vary depending on which array type you have.
The process outlined above can be followed for basically any storage array that is connected to VMware hosts. I highly recommend looking through VMware’s Compatibility Guide and configuring your storage according to their recommendations.