Thecus N16000 Series User Manual page 50

The Auto Failback function under Heartbeat Communications on the
High-Availability page in the UI automatically brings the original active server back
online when it is fully repaired to again act as the active server and put the standby
server back in standby mode.
When auto failback is off (default): After the original active server is damaged and
then returned to a healthy state, the original standby server will remain active and
the original active server will go into standby mode. The servers will exchange
roles.
When auto failback is on: After the original active server is damaged and then
returned to a healthy state, the original standby server will go back into standby
mode and the original active server will become active again. The servers return to
their original roles.
With or without auto failback, synchronization will begin immediately without a
break in service when the damaged server returns. The roles described above are
assumed immediately and do not need to wait for synchronization. The virtual IP will
always be mapped to the current active server.
WARNING
When the original active server rejoins the HA
environment, it will be updated with the newer
data from the original standby server to
synchronize for HA. Please be aware that the data
on the original active server will be replaced by
the data from the original standby server.
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