What does "Not-Reachable" mean when running the command fcp ping-initiator show?

Applies to

ONTAP 9

Answer

• The command vserver fcp ping-initiator show  shows "not-reachable" response for the host WWPN.

Example:

SAN::*> vserver fcp ping-initiator show -vserver test_svm -wwpn 20:00:00:00:00:00:00:00
                            Node       Logical   Ping        Extended
Vserver   WWPN              Name       Interface Status      Status
--------- ----------------- ---------- --------- ----------- -----------------
test_svm
          20:00:00:00:00:00:00:00
                            SAN8080-01 SAN8080-01_fcoe_lif_1
                                                 not-reachable -
          20:00:00:00:00:00:00:00
                            SAN8080-02 SAN8080-02_fcoe_lif_1
                                                 not-zoned -
 

• In the above example LIF SAN8080-01_fcoe_lif_1 is not-reachable. 
• “Not reachable” status is seen when ELS_Echo request that was sent to the host was not returned. It does not mean that the host is not logged in to storage or connected to storage in every case, as ELS_Echo request's are not supported on all devices.
• We need to check if the host supports and responds to the ELS_Echo request.
• Switch and host HBA vendor documentation should show if ELS_Echo requests are supported. 
• On the SAN switch, we can use “fcping” command to validate link connectivity to a single device or between a pair of devices.
• fcPing on Fabric OS Sends a Fibre Channel Extended Link Service (ELS) Echo request to a pair of ports or to a single destination.This command performs the following functions:
  • Checks the zoning configuration for the two ports specified.
  • Generates an ELS ECHO request to the source port specified and validates the response.
  • Generates an ELS ECHO request to the destination port specified and validates the response.

Note-
There are some devices that do not support the ELS ECHO request. In such cases, the response could be either an ELS reject or a request timeout.
When a device does not respond to the ELS request, further debugging is required; however, do not assume that the device is not connected.

• By default, fcPing sends five ELS_Echo requests to each port.
• When a device does not respond to the ELS_Echo request, further debugging may be needed to determine, whether the device does not support ELS_Echo, or whether the request is rejected for some other reason.
• Regardless of the device’s zoning configuration, the fcping command sends the ELS frame to the destination port.
• A destination device can take any one of the following actions:
  • Send an ELS Accept to the ELS request.
  • Send an ELS Reject to the ELS request.
  • Ignore the ELS request.

•  Below is one example of device that accepts the request and another device that rejects the request, please refer below-

device:admin> fcping 10:00:00:00:c9:29:0e:c4 21:00:00:20:37:25:ad:05
Source: 10:00:00:00:c9:29:0e:c4
Destination: 21:00:00:20:37:25:ad:05
Zone Check: Not Zoned

Pinging 10:00:00:00:c9:29:0e:c4 [0x20800] with 12 bytes of data:
received reply from 10:00:00:00:c9:29:0e:c4: 12 bytes time:1162 usec
received reply from 10:00:00:00:c9:29:0e:c4: 12 bytes time:1013 usec
received reply from 10:00:00:00:c9:29:0e:c4: 12 bytes time:1442 usec
received reply from 10:00:00:00:c9:29:0e:c4: 12 bytes time:1052 usec
received reply from 10:00:00:00:c9:29:0e:c4: 12 bytes time:1012 usec
5 frames sent, 5 frames received, 0 frames rejected, 0 frames timeout
Round-trip min/avg/max = 1012/1136/1442 usec

Pinging 21:00:00:20:37:25:ad:05 [0x211e8] with 12 bytes of data:
Request rejected by 21:00:00:20:37:25:ad:05: Command not supported: time: 1159 usec
Request rejected by 21:00:00:20:37:25:ad:05: Command not supported: time: 1006 usec
Request rejected by 21:00:00:20:37:25:ad:05: Command not supported: time: 1008 usec
Request rejected by 21:00:00:20:37:25:ad:05: Command not supported: time: 1038 usec
Request rejected by 21:00:00:20:37:25:ad:05: Command not supported: time: 1010 usec
5 frames sent, 0 frames received, 5 frames rejected, 0 frames timeout

Additional Information

• "not-reachable” state will not have any issues during Ontap Upgrade as long as we have verified the connectivity from the host to storage works all fine and we can access the luns via all the paths.     
• An example of an appropriately zoned and responsive host.

Example:

SAN8080::*> vserver fcp ping-initiator show -vserver test_svm -wwpn 20:00:00:00:00:00:00:00
                            Node       Logical   Ping        Extended
Vserver   WWPN              Name       Interface Status      Status
--------- ----------------- ---------- --------- ----------- -----------------
vserver_1
          20:00:00:00:00:00:00:00
                         node_1
                                    lif_1     reachable wwpn-logged-in
                                    

• If there is any delay in the ELS_ECHO acknowledgement or request timeout from the host, even in that case, we will see "not-reachable" response for the host WWPN.

• fcPing Command on Brocade Switch