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Description
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Illustration
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Server #1 fails.
Server #2 cannot access Server #1 and switches to SECONDARY ALONE state automatically.
The watchdog determines that Server #1 is not responding.
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The watchdog instructs Server #2 to switch to PRIMARY ALONE state by using the command:
ADMIN COMMAND 'hotstandby set primary alone';
Applications access data from Server #2 (new primary server).
Server #2 saves all transactions in the transaction log.
The watchdog continues to monitor responsiveness of servers.
Note If the transaction log on Server #2 fills up before the network connection is fixed, you might have to switch Server #2 to STANDALONE state.
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The administrator brings Server #1 back up as the secondary server.
The watchdog instructs Server #2 to connect to Server #1 by using the command:
ADMIN COMMAND 'hotstandby connect';
Server #1 reads and applies the transactions from the transaction log on Server #2.
Note If you switched Server #2 to STANDLONE state, you must copy the database from Server #2 to Server #1 before you reconnect the servers, see Synchronizing primary and secondary servers for details.
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