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Communication problems

Use this information to resolve issues related to the communication between devices.

A compute node cannot communicate with the CMM 2 on the data network​

Note

Communications errors from compute nodes can take up to 20 minutes to appear in the CMM 2 event log.

Complete the following steps until the problem is solved:

  1. Make sure that all ports in the connection path are enabled and that you can ping the CMM 2. If you are unable to ping the CMM 2, see A compute node in the chassis cannot ping the CMM 2 on management network.

  2. Make sure that the protocols that you are using are enabled. By default, only secure protocols are enabled, for example, SSH and HTTPS.

  3. Make sure that you can log into the CMM 2. If you are unable to log in to the CMM 2, see Cannot log in to CMM 2.

  4. Reset the CMM 2 to the default settings by pressing the reset button on the CMM 2.

    Press and hold the button for 10 seconds to reset the CMM 2 configuration settings. All user modified configuration settings are reset to the factory default values.

A compute node cannot communicate with an I/O module​

Complete the following steps until the problem is solved:

  1. Make sure that all ports in the connection path are enabled and that you can ping the I/O module. If you are unable to ping the I/O module, see A compute node cannot ping an I/O module.

  2. Make sure that the protocols that you are using are enabled. By default, only secure protocols are enabled, for example, SSH and HTTPS.

  3. Make sure that you can log into the I/O module. If you are unable to log in to the I/O module, see Cannot log in to I/O module.

  4. Use a serial cable to connect to the I/O module to further isolate the problem. You can also link to the I/O module through an external Ethernet port.

One or more compute nodes cannot communicate with the SAN​

Complete the following steps until the problem is solved:
  1. Make sure that:

    • The I/O module is powered on and the appropriate ports are enabled on the I/O module.

    • The CMM 2 has reported that the I/O module has completed POST and that no errors have been reported in the logs.

    • The SAN device is powered on and is functional.

    • All cables between the I/O module and the SAN device are properly connected and secure, and that the activity LEDs are lit on the appropriate ports.

  2. See the documentation for the I/O module for additional information about troubleshooting SAN connectivity or network connectivity issues.