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Add warning about SUPER-users to Switchover Limitations documentation

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Esa Korhonen 2018-01-16 12:20:18 +02:00
parent 1d211ecee2
commit 71f74ea0d2
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Documentation/Monitors/MariaDB-Monitor.md
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@ -277,6 +277,18 @@ The backends must all use GTID-based replication, and the domain id should not
change during a switchover or failover. Master and slaves must have
well-behaving GTIDs with no extra events on slave servers.
Switchover requires that the cluster is "frozen" for the duration of the
operation. This means that no data modifying statements such as INSERT or UPDATE
are executed and the GTID position of the master server is stable. When
switchover begins, the monitor sets the global *read_only* flag on the old
master backend to stop any updates. *read_only* does not affect users with the
SUPER-privilege so any such user can issue writes during a switchover. These
writes have a high chance to break replication, because the write may not be
replicated to all slaves before they switch to the new master. To prevent this,
any users who commonly do updates should not have the SUPER-privilege. For even
more security, the only SUPER-user session during a switchover should be the
MaxScale monitor user.
### Configuration parameters
#### `auto_failover`