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Document mysqlmon server state backup

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The functionality is now documented in the MySQL Monitor documentation.
This commit is contained in:
Markus Mäkelä 2017-03-17 11:29:05 +02:00
parent 44f53663ea
commit 85b8a963bd
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18
Documentation/Monitors/MySQL-Monitor.md
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@ -200,6 +200,24 @@ external agent that automatically reintegrates failed servers into the
cluster. One of these agents is the _replication-manager_ which automatically
configures the failed servers as new slaves of the current master.
## MySQL Monitor Crash Safety
Starting with MaxScale 2.2.0, the mysqlmon module keeps an on-disk journal of
the latest server states. This change makes the monitor crash-safe when options
that introduce states are used. It also allows the monitor to retain stateful
information when MaxScale is restarted.
Options that introduce states into the monitoring process are the
`detect_stale_master` and `detect_stale_slave` options, both of which are
enabled by default.
The default location for the server state journal is in
`/var/lib/maxscale/<monitor name>/mysqlmon.dat` where `<monitor name>` is the
name of the monitor section in the configuration file. If MaxScale crashes or is
shut down in an uncontrolled fashion, the journal will be read when MaxScale is
started. To skip the recovery process, manually delete the journal file before
starting MaxScale.
## Example 1 - Monitor script
Here is an example shell script which sends an email to an admin when a server goes down.

8
Documentation/Release-Notes/MaxScale-2.2.0-Release-Notes.md
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@ -35,6 +35,14 @@ The commands can be issued, but have no effect.
## New Features
### MySQL Monitor Crash Safety
The MySQL monitor keeps a journal of the state of the servers and the currently
elected master. This information will be read if MaxScale suffers an
uncontrolled shutdown. By doing the journaling of server states, the mysqlmon
monitor is able to keep track of stale master and stale slave states across
restarts and crashes.
### Avrorouter `deflate` compression
The Avrorouter now supports the `deflate` compression method. This allows the