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Diffstat (limited to 'src/man/include/failover.xml')
| -rw-r--r-- | src/man/include/failover.xml | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/src/man/include/failover.xml b/src/man/include/failover.xml new file mode 100644 index 000000000..efe3ee424 --- /dev/null +++ b/src/man/include/failover.xml @@ -0,0 +1,42 @@ +<refsect1 id='failover'> + <title>FAILOVER</title> + <para> + The failover feature allows back ends to automatically switch to + a different server if the primary server fails. + </para> + <refsect2 id='failover_syntax'> + <title>Failover Syntax</title> + <para> + The list of servers is given as a comma-separated list; any + number of spaces is allowed around the comma. The servers are + listed in order of preference. The list can contain any number + of servers. + </para> + </refsect2> + <refsect2 id='failover_mechanism'> + <title>The Failover Mechanism</title> + <para> + The failover mechanism distinguishes between a machine and a + service. The back end first tries to resolve the hostname of a + given machine; if this resolution attempt fails, the machine is + considered offline. No further attempts are made to connect + to this machine for any other service. If the resolution + attempt succeeds, the back end tries to connect to a service + on this machine. If the service connection attempt fails, + then only this particular service is considered offline and + the back end automatically switches over to the next service. + The machine is still considered online and might still be tried + for another service. + </para> + <para> + Further connection attempts are made to machines or services + marked as offline after a specified period of time; this is + currently hard coded to 30 seconds. + </para> + <para> + If there are no more machines to try, the back end as a whole + switches to offline mode, and then attempts to reconnect + every 30 seconds. + </para> + </refsect2> +</refsect1> |