Thecus N8900 series User Manual page 108

After Secondary server has communicated with Primary Server successfully,
then the state will changed:
Click "Yes" to reboot both Primary and Secondary server.
If the communication is failed then you will have error message as below.
WARNING
Conditions in which the secondary server will take over to play role as
Active:
1. Primary server RAID is damaged
2. Loss of the primary server's data port connection
3. Primary server goes down for any other reason
When the primary server encounters the above-mentioned situations, the
secondary server (PMS) will immediately take over to play role as active. The
secondary server's system log will show "HA changed to active, getting resources",
and "Healthy: The RAID [HA] on system [PMS] is healthy now."
Please be sure that "Secondary" unit volume
size must be larger then "Primary" unit. Or
the HA synchronize will result failed.
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