A sample output of the command:

Router# show vdc
vdc_id  vdc_name                          state               mac
------  --------                          -----               ----------
1       switch                            active              00:18:ba:d8:3f:fd
2       Payroll                           active              00:18:ba:d8:3f:fe
3       RSUDAM2                           active              8c:b6:4f:e9:f3:42
4       RNORM6                            active              10:8c:cf:1d:fd:42

It gives the MAC address of individual VDC belong to the Nexus 7k Switch. This is used to update default VDC ComposedOf relation with the other VDCs that are created.

Note:

If the default VDC goes down, then the other VDCs are also impacted. However, IP 9.1 generates only one Down root cause instead of four individual VDC Down problems.