Data Domain: Prepare a High Availability - HA - system for component replacement

Summary: This Article provides the steps involved in preparing a High Availability (HA) system for a disruptive (not hot-swap) part replacement.

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Instructions

Affected Systems:

  • All Data Domain Models supporting High Availability (HA)
  • Disruptive (not hot swap) replacement of components on HA systems

Summary:

  • Components that require downtime during replacement (such as NVRAM, DIMMs, SP, SLICs) require additional steps when undertaken on DD HA systems
  • For HA systems, the node where the maintenance activity is performed should be set as the standby node, so the other node can remain online and continue customer operations.
  • Hot-swap components (disks and Power Supplies) can be replaced as normal.

Prepare the HA system for component replacement:
 

1. Enter the management IP address of the node on which the maintenance activity is to be performed into a web browser and login as sysadmin.
2. Verify the node number and role in the upper right corner of the screen. If the affected node is the standby node, go to step 4.

kA5f1000000L0IBCA0_1_0
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Alternatively, if UI access is not possible, verify the Node from DD-CLI prompt by entering the command #filesystem status
The Active/Stand-by nodes return the following:
 
Standby Node Example: 
sysadmin@DDHA-p1(standby:1)# filesys status
**** This command is not available on standby node.
Active Node Example: 
sysadmin@DDHA-p0(active:0)# filesys status
The filesystem is enabled and running.

 
3. If the affected node is the active node, run the #ha failover command to initiate a failover.
  • The failover process takes ~10 minutes to complete while the local node reboots itself.
  • Warning: During failover, the filesystem encounters momentary downtime as it is restarted up on the standby node
Step 3 Example: 
sysadmin@ddha-p1(active:1)# ha failover
This operation will initiate a failover from this node. The local node will reboot.
        Do you want to proceed? (yes|no) [no]: yes
Failover operation initiated. Run 'ha status' to monitor the status..

sysadmin@ddha-p1(active:1)# ha status
HA System name:       ddha.foo.com
HA System status:     degraded
Node Name                       Node id   Role      HA State
-----------------------------   -------   -------   ------------
ddha-p1.foo.com   1         standby   failing-over
ddha-p0.foo.com   0         active    taking-over
-----------------------------   -------   -------   ------------
 
4. Run the #ha offline command on the node (Stand-by) where the maintenance activity is being performed.
5. Run the #ha status command to verify the active node is online or degraded and the standby node is offline. 
sysadmin@DDHA-p1(standby:1)# ha offline
This operation will cause the ha system to no longer be highly available.
         Do you want to proceed? (yes|no) [no]: yes
Standby node is now offline.

sysadmin@DDHA-p1(standby:1)# ha status
HA System Name: DDHA.foo.com
HA System Status: highly available
Node Name Node ID Role HA State
-------------------------- --------- --------- --------
DDHA-p0.foo.com 0 standby offline   <<<-------------- NOTE
DDHA-p1.foo.com 1 active degraded
-------------------------------------------------------

6. [Shut down the standby system using the #system poweroff command to allow the proper shut-down of the file system and other system components.
  • The system poweroff command is completed when the front panel blue LED turns off.         
7. [Disconnect the four AC power cables from the rear of the system.         
8. Replace the affected component as per the documented procedure. 
9. Following successful part replacement, reapply AC power and power on the DD unit. 
10. Run the #ha online command on the standby node to bring the HA configuration back online. 
11. Optional: Failback to original 'Active' node
If the system was failed over to the standby node prior to component replacement, perform a failback to restore the original active node.

Steps:

  1. Run the ha status command to verify that the HA pair is healthy and capable of failover.
  2. On the current active node, run the ha failover command to initiate failback.
  3. Confirm that the original active node is restored and operational.

Affected Products

Data Domain

Products

Data Domain, Data Domain Deduplication Storage Systems, DD9500 Appliance, DD9800 Appliance
Article Properties
Article Number: 000010752
Article Type: How To
Last Modified: 26 Sept 2025
Version:  6
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