Symptom:
copy r s failing on nexus 9508.

switch# copy r s
[########################################]  98% Configuration update aborted: timed out

Following errors seen in logs:

2015 Sep 22 20:37:44 MDFLD-MVD1 %SYSMGR-2-CFGWRITE_ABORTED_CONFELEMENT_RETRIES: Copy R S failed as config-failure retries are ongoing. Type "show nxapi retries" for checking the ongoing retries.
2015 Sep 22 20:37:44 MDFLD-MVD1 %SYSMGR-3-CFGWRITE_SRVFAILED: Service "confelem" failed to store its configuration (error-id 0x00000079).
2015 Sep 22 20:38:14 MDFLD-MVD1 %SYSMGR-3-BASIC_TRACE: process_show_running_req: PID 11354 with message rvcd on vdc 1 . 
2015 Sep 22 20:38:14 MDFLD-MVD1 %SYSMGR-3-BASIC_TRACE: process_show_running_req: PID 11354 with message last vdc = 1 . 
2015 Sep 22 20:38:14 MDFLD-MVD1 %SYSMGR-2-CFGWRITE_USER_ABORT: Configuration copy aborted by the user.
2015 Sep 22 20:38:44 MDFLD-MVD1 %SYSMGR-3-CFGWRITE_SRVFAILED: Service "ethpm" failed to store its configuration (error-id 0x0000007C).
2015 Sep 22 20:42:44 MDFLD-MVD1 %SYSMGR-3-CFGWRITE_SRVTIMEOUT: Service "eth_port_channel" failed to store its configuration in the timeout period
2015 Sep 22 20:42:44 MDFLD-MVD1 %SYSMGR-2-CFGWRITE_ABORTED: Configuration copy aborted.
2015 Sep 22 20:42:45 MDFLD-MVD1 %SYSMGR-3-CFGWRITE_FAILED: Configuration copy failed (error-id 0x401E0045).

Conditions:
configuring switchport on an L3 port-channel with sub-interfaces