Celerra/VNX Unified: How to fail over / fail back a Control Station (User Correctable)

Summary: How-to guide on steps to change primary/secondary relationships of the control stations

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Symptoms


Users are unable to access Unisphere using the Primary Control Station IP address.  
/nas/ and nas_commands are failing or not found
nas_checkup will report an error to Unisphere (See notes)

Cause

Multiple issues can cause a CS failover.

Resolution

Use /nasmcd/getreason to determine the status of the control stations. (getreason output showing a failed over state.)
 
[nasadmin@VNXLab ~]$ /nasmcd/getreason
11 - slot_0 secondary control station
10 - slot_1 primary control station
 5 - slot_2 contacted
 5 - slot_3 contacted
 5 - slot_4 contacted
 
Control station can be failed back using multiple methods.

If on slot_0, you will see and use the following:
 
slot_0 secondary control station
Would you like to log into the Primary Control Station? (yes or [no]) no
 
[nasadmin@VNXLab ~]$ su
Password:
[root@VNXXLab nasadmin]# /nasmcd/sbin/cs_standby -takeover
Taking over as Primary Control Station...succeeded

(This will take 1-3 minutes.)

If on slot_1, you will see and use the following:
 
slot_1 primary control station 
 
[nasadmin@BottleCapsCS0 ~]$ su
Password:
[root@VNXLab nasadmin]# /nasmcd/sbin/cs_standby -failover
 
The system will reboot, do you wish to continue? [yes or no]: yes
Failing over from Primary Control Station.
 
Broadcast message from root (pts/2) (Mon Aug 11 17:36:21 2014):
 
The system is going down for reboot NOW!
 
--OR--
 
[nasadmin@VNXLab ~]$ su
Password:
[root@VNXLab nasadmin]# reboot

Broadcast message from root (pts/0) (Mon Aug 11 16:59:29 2014):

The system is going down for reboot NOW!
(This will take 1-3 minutes)

Additional Information

nas_checkup error. 
 
Control Station: Check if primary is active
Error HC_CS_14505082897: Slot 0 is not the primary Control Station
Action :
  1. Use various logs on the system to determine the problem that caused the Control Stations to fail over. Make sure that you know what the cause of the failure was and that it has been fixed before attempting to failback the Control Stations.
  2. On the Control Station in slot 1, run command "/nasmcd/sbin/cs_standby -failback". The Control Station in slot 1 will reboot and the Control Station in slot 0 will become the primary.
  3. Wait 5 minutes for services to come up fully and verify that the problem has been fixed by logging into both Control stations as nasadmin. When you log into the Control Station in slot 0, it should log you in normally. When you log into the Control Station in slot 1, it should tell you that slot 1 is not the primary Control Station.

Getreason output showing a failed over state.
 
[nasadmin@VNXLab ~]$ /nasmcd/getreason
11 - slot_0 secondary control station
10 - slot_1 primary control station
 5 - slot_2 contacted
 5 - slot_3 contacted
 5 - slot_4 contacted

Affected Products

VNX2 Series

Products

eNAS, VNX1 Series, VNX2 Series, VNX/VNXe
Article Properties
Article Number: 000025261
Article Type: Solution
Last Modified: 07 Nov 2025
Version:  4
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