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MXS-3017 Fix MariaDBMonitor documentation

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The descriptions of several settings were not updated for 2.4.
This commit is contained in:
Esa Korhonen
2020-06-01 16:41:17 +03:00
parent 727aeb4a08
commit f74035dc63
1 changed files with 22 additions and 41 deletions
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63
Documentation/Monitors/MariaDB-Monitor.md
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@ -141,34 +141,22 @@ Is effectively always on. The monitor uses the "Seconds_Behind_Master"-field of
### `detect_stale_master` ### `detect_stale_master`
Allow previous master to be available even in case of stopped or misconfigured Deprecated and ignored.
replication.
Starting from MaxScale 2.0.0 this feature is enabled by default. It is disabled
by default in MaxScale 1.4.3 and below.
This allows services that depend on master and slave roles to continue
functioning as long as the master server is available. This is a situation
which can happen if all slave servers are unreachable or the replication
breaks for some reason.
```
detect_stale_master=true
```
### `detect_stale_slave` ### `detect_stale_slave`
Treat running slaves servers without a master server as valid slave servers. Boolean, default: ON. Treat running slaves servers without a running master as
valid slave servers.
This feature is enabled by default. If a slave server does not have a live connection to the master, either because
the master is *Down* or because the slave cannot connect, replication is
effectively paused. The slave may still have up-to-date data and may be usable
for reading. *detect_stale_slave* controls whether such a slave is marked *Slave*
and used for query routing.
If a slave server loses its master server, the replication is considered broken. If this feature is disabled, a server is considered a valid slave only if it has
With this parameter, slaves that have lost their master but have been slaves of a running master server and the replication connection is working properly. In a
a master server can retain their slave status even without a master. This means multi-level topology, each link would also need to be replicating properly.
that when a slave loses its master, it can still be used for reads.
If this feature is disabled, a server is considered a valid slave if and only if
it has a running master server monitored by this monitor.
``` ```
detect_stale_slave=true detect_stale_slave=true
@ -184,29 +172,22 @@ Deprecated and unused as of MaxScale 2.3. Can be defined but is ignored.
### `ignore_external_masters` ### `ignore_external_masters`
Ignore any servers that are not monitored by this monitor but are a part of the Boolean, default: OFF. Ignore any servers that are not monitored by this monitor
replication topology. This option was added in MaxScale 2.1.12 and is disabled but are a part of the replication topology.
by default.
MaxScale detects if a master server replicates from an external server. When An external server is a server not monitored by this monitor. If a server is
this is detected, the server is assigned the `Slave` and `Slave of External replicating from an external server, it typically gains the *Slave of External
Server` labels and will be treated as a slave server. Most of the time this Server*-status. If this setting is enabled, the status is not set.
topology is used when MaxScale is used for read scale-out without master
servers, a Galera cluster with read replicas being a prime example of this
setup. Sometimes this is not the desired behavior and the external master server
should be ignored. Most of the time this is due to multi-source replication.
When this option is enabled, all servers that have the `Master, Slave, Slave of
External Server, Running` labels will instead get the `Master, Running` labels.
### `detect_standalone_master` ### `detect_standalone_master`
Detect standalone master servers. This feature takes a boolean parameter and is Boolean, default: ON. This setting controls whether a standalone server can be a
enabled by default. master. A standalone server is a server from which no other server in the
cluster is attempting to replicate from.
This setting controls whether a standalone server can be a master. A standalone If disabled, a solitary server cannot gain *Master*-status. If MaxScale cannot
server is a server from which no other server in the cluster is attempting to connect to a slave but the slave was previously replicating, then the master is
replicate from. In most cases this should be left on. still assumed to have a slave, and this setting does not apply.
### `failcount` ### `failcount`