Dell FlexAddress with Redundant CMCs “Not Working”

Problem Description

With Dell’s FlexAddress technology enabled on a Dell PE M1000e, after changing a HBA or network card that has a different WWN/MAC than the original (it should, of course!), the FlexAddress WWN/MAC assignment does not take effect, and the mezzanine card’s OEM WWN/MAC prevails.

Hardware Topology

  • Dell PowerEdge M1000e chassis
  • Redundant CMC (chassis management controller) modules
  • single Dell FlexAddress SD card installed in one of the CMC modules
  • The other CMC (redundant) module does not contain a FlexAddress SD card
  • Dell Blade (mine are M600-series half-height)
  • Fabric A enabled (for onboard networking), or one or more mezzanine cards installed for Fabric B or Fabric C


One or more of the following steps are applicable:

  1. Ensure the CMC that contains the Dell FlexAddress SD card is active (not in standby). See page 179 of the “Dell PowerEdge M1000e Chassis Management Controller Firmware Version 5.0 User’s Guide“. If it is in standby, a graceful failover can be performed by invoking the cmcchangeover command. This will only affect out-of-band management (OOBM), and not the production system.
  2. Perform a virtual reseat (not restart) of the blade module, e.g. for blade in slot 10 racadm serveraction -m server-10 reseat -f . This is a “known” issue in the context of upgrading mezzanine card firmware, see Flex Address doesn’t work after Broadcom FW Update. This assumes the specific blade is down for maintenance anyway.
  3. Ensure the Dell FlexAddress SD card is not locked. With the angled corner to the top right, the sliding lever should be in the “forward” or “up” position. The FlexAddress card is installed in the SD card slot on the underside of the CMC board; the CMC module should be completely removed to inspect this. This procedure also only affects OOBM. (Hint: stick around to hear the fans spin up after re-inserting the CMC module!)
  4. Ensure that FlexAddress is enabled for the specific chassis slot. This can be done within the CMC web interface GUI, or telnet/SSH/serial CLI. Enabling/Disabling FlexAddress can only be performed when a blade module is installed in the slot, with iDRAC initialized (I think?), and the state of the blade is powered off. Changing the state of FlexAddress for a powered-on blade is not possible.
  5. Alternatively, using two Dell FlexAddress SD Cards – one in each CMC – will avoid guessing which CMC has it installed.