Skip to main content

Preparing for CMM redundancy

Use these instructions to prepare your CMM for redundant operation.

To prepare your CMM for redundancy, complete the following steps:

  1. Install the standby CMM in the available CMM bay.
  2. Wait approximately 2 minutes while the primary CMM transfers firmware and configuration information to the standby CMM.
    Note
    • Whenever power is restored to a Flex System chassis that has two functional CMMs, the CMM in CMM bay 1 is typically prioritized as the primary CMM, even if the CMM in CMM bay 2 was the primary CMM before power was removed, however, sometimes the CMM in bay 2 will be prioritized, making it the primary CMM.
    • For the most recent versions of optional management software, that you can use to manage a Lenovo Flex System chassis with a redundant CMM, go to Lenovo Datacenter Support site.
  3. Configure CMM failover response:
    • Configure failover response for loss of the primary CMM:
      Note
      • If you enable IP address swapping during failover with both CMMs set to the same static IP address, you must disable DHCP.
      • In the CMM web interface, CMM failover is configured on the Advanced Failover page on the Management Module Properties page (select Properties from the Mgt Module Management menu). All fields and options are fully described in the CMM web interface online help.
      • In the CMM CLI, use the advfailover command (see advfailover command for information about command use).
    • Configure failover response for loss of the management network (uplink) connection to the primary CMM:
      Note
      Failure of the management network (uplink) connection to the primary CMM is indicated when all of the following conditions occur:
      • Loss of CMM eth0 input and output packets
      • Network noise
      • Failures when pinging the CMM gateway and a designated station
      • In the CMM web interface, uplink failover is configured on the Ethernet page on the Network Protocol Properties page (select Network from the Mgt Module Management menu). All fields and options are fully described in the CMM web interface online help.
      • In the CMM CLI, use the uplink command (see uplink command for information about command use).
      • If a Flex System chassis is set up for redundant CMM operation and both CMMs experience an unrecoverable failure, the chassis will attempt to switch control between the CMMs indefinitely. If this condition occurs, replace one CMM to return the chassis to operation or replace both CMMs to return the chassis to redundant operation. Depending on how each CMM failed, you might need to configure the replacement CMM or restore its configuration from a backup, if one is available. A failure of both CMMs might be an indication of other problems with the Flex System chassis; make sure that the chassis is operating properly before replacing either CMM. See Troubleshooting chassis for information about diagnosing problems with a Flex System chassis.