Configuring Cisco MDS 9148S 16G 48 FC SAN switch with multipath for HA

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Configuring Cisco MDS 9148S 16G 48 FC SAN switch with multipath for HA

In case of network switches we need to use stacking and Port aggregation (also called link aggregation, nic bonding, IEEE 802.3ad, etc.) for allowing HA. This is necessary as without corresponding configuration there would be switching loops which would get detected by Spanning Tree Protocol (STP), which would cause redundant links to remain inactive.

In contrast on stroage switches we do not have looping issues. Further we can let the end-host (Server or initiator) see multiple paths to a target (Volume shared by Storage server) as OS multipath drivers can understand and show only one single virtual volume for all paths to the same volume.

Thus, to configure two storage switches with multipathing for providing HA use:

1. If the end-point (server or initiator) is going to virtualize HBA card and present virtual WWN numbers for each VM then we need to enable npiv on storage switch. For enabling npiv on storage switch use:

   config t
   feature npiv

   Note that many guides, pages, manuals, etc. would show how to enable npv mode. npv mode is not required and would not help in any way for virtualized WWN

2. For each port connected to virtualized servers that needs npiv use:

   config t
   interface fc 1/7 - 10
   switport mode F
   no shut

3. Add all hosts (server or initiator) ports to vsan database using:

   config t
   vsan database
   vsan 1 interface fc1/7

4. Reboot of server along with all VMs might be required before the virtual wwn numbers shown up on switch. This is 100% required for Suse IBM Power-VM base (Host) along with all VMs (LPARS).
5. Create (fc)aliases, zones and zoneset using command-line in same order.

Please note that when (fc)aliases are used the shown run shows all zones twice. Once with aliases replaced with wwn numbers and other time with zones with alias names. In such cases if any alias is remapped to another wwn number then zone reactivation using commands such as:

   zoneset activate name <zoneset-name> vsan 1

might be necessary for changed alias to take effect for active zoneset.

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