Verifying the existence of two paths: storage show disk command

You should verify that your Data ONTAP system is configured with two paths to an array LUN so that there is a secondary path in case the primary path fails or is taken offline.

1. Enter the following command to show the primary and secondary paths to array LUNs: storage show disk -p all
   The system displays information similar to the following:

   PRIMARY 	PORT             SECONDARY  PORT           SHELF BAY ADAPTER
   -------------------- ---- ------------------------- ---- ---
   vnmc4500s32:4.127L1    -    vnmc4500s33:19.127L1   -     -    -   0a
   vnmc4500s32:4.127L12   -    vnmc4500s33:19.127L12  -     -    -   0a
   vnmc4500s33:19.127L2   -    vnmc4500s32:4.127L2    -     -    -   0c
   vnmc4500s33:19.127L13  -    vnmc4500s32:4.127L13   -     -    -   0c

   Note: When you use the all variable, adapters are displayed, but unassigned LUNs are not visible.
2. Determine whether a primary path and a secondary path to the array LUNs are shown.
   If you do not see a primary and secondary path, check the zoning, host group configuration, and cabling.

   Note: Do not continue with testing until you see two paths.

   For information about troubleshooting pathing, see the FlexArray Virtualization Installation Requirements and Reference Guide
3. Look at the adapters shown to see whether all paths are on a single adapter.
   If you see both paths through one port (for example, both paths through the 0c port), this is an indication that the back-end zoning is redundantly crossed. This is not a supported configuration.

   Note: Data ONTAP changes the path to array LUNs, as necessary, for load balancing. Therefore, the primary and secondary paths for a given array LUN can change when the storage show disk command is issued at different times.