github.com/niedbalski/juju@v0.0.0-20190215020005-8ff100488e47/acceptancetests/repository/charms/mysql/README.md (about)

     1  # Overview
     2  
     3  [MySQL](http://www.mysql.com) is a fast, stable and true multi-user, multi-threaded SQL database server. SQL (Structured Query Language) is the most popular database query language in the world. The main goals of MySQL are speed, robustness and ease of use.
     4  
     5  This charm also can deploy [Percona Server](http://www.percona.com/software/percona-server) is fork of MySQL by Percona Inc. which focuses on maximizing performance, particularly for heavy workloads. It is a drop-in replacement for MySQL and features XtraDB, a drop-in replacement for the InnoDB storage engine.
     6  
     7  # Usage
     8  
     9  ## General Usage
    10  
    11  To deploy a MySQL service:
    12  
    13      juju deploy mysql
    14  
    15  Once deployed, you can retrive the MySQL root user password by logging in to the machine via `juju ssh` and readin the `/var/lib/mysql/mysql.passwd` file. To log in as root MySQL User at the MySQL console you can issue the following:
    16  
    17      juju ssh mysql/0
    18      mysql -u root -p=`cat /var/lib/mysql/mysql.passwd`
    19  
    20  # Scale Out Usage 
    21  
    22  ## Replication
    23  
    24  MySQL supports the ability to replicate databases to slave instances. This
    25  allows you, for example, to load balance read queries across multiple slaves or
    26  use a slave to perform backups, all whilst not impeding the master's
    27  performance.
    28  
    29  To deploy a slave:
    30  
    31      # deploy second service
    32      juju deploy mysql mysql-slave
    33  
    34      # add master to slave relation
    35      juju add-relation mysql:master mysql-slave:slave
    36  
    37  Any changes to the master are reflected on the slave.
    38  
    39  Any queries that modify the database(s) should be applied to the master only.
    40  The slave should be treated strictly as read only.
    41  
    42  You can add further slaves with:
    43  
    44      juju add-unit mysql-slave
    45  
    46  ## Monitoring
    47  
    48  This charm provides relations that support monitoring via either [Nagios](https://jujucharms.com/precise/nagios) or [Munin](https://jujucharms.com/precise/munin/). Refer to the appropriate charm for usage.
    49  
    50  # Configuration
    51  
    52  You can tweak various options to optimize your MySQL deployment:
    53  
    54  * max-connections - Maximum connections allowed to server or '-1' for default.
    55  
    56  * preferred-storage-engine - A comma separated list of storage engines to
    57    optimize for. First in the list is marked as default storage engine. 'InnoDB'
    58    or 'MyISAM' are acceptable values.
    59  
    60  * tuning-level - Specify 'safest', 'fast' or 'unsafe' to choose required
    61    transaction safety. This option determines the flush value for innodb commit
    62    and binary logs. Specify 'safest' for full ACID compliance. 'fast' relaxes the
    63    compliance for performance and 'unsafe' will remove most restrictions.
    64  
    65  * dataset-size - Memory allocation for all caches (InnoDB buffer pool, MyISAM
    66    key, query). Suffix value with 'K', 'M', 'G' or 'T' to indicate unit of
    67    kilobyte, megabyte, gigabyte or terabyte respectively. Suffix value with '%'
    68    to use percentage of machine's total memory.
    69  
    70  * query-cache-type - Specify 'ON', 'DEMAND' or 'OFF' to turn query cache on,
    71    selectively (dependent on queries) or off.
    72  
    73  * query-cache-size - Size of query cache (no. of bytes) or '-1' to use 20%
    74    of memory allocation.
    75  
    76  Each of these can be applied by running:
    77  
    78      juju set <service> <option>=<value>
    79  
    80  e.g.
    81  
    82      juju set mysql preferred-storage-engine=InnoDB
    83      juju set mysql dataset-size=50%
    84      juju set mysql query-cache-type=ON
    85      juju set mysql query-cache-size=-1
    86  
    87  Deploying Percona Server is an option in this charm, you can do so by editing the `flavor` option:
    88  
    89      juju set mysql flavor=percona
    90  
    91  WARNING: Migrating from MySQL to Percona Server in this fashion is currently a one-way migration, once you migrate you cannot migrate back via Juju. 
    92  
    93  # MySQL and Percona Server Contact Information
    94  
    95  - [MySQL Homepage](http://www.mysql.com)
    96  - [MySQL Bug Tracker](http://bugs.mysql.com/)
    97  - [Percona Server Homepage](http://www.percona.com/software/percona-server)
    98  - [Percona Server Bug Tracker](https://bugs.launchpad.net/percona-server/)
    99  - [MySQL mailing lists](http://lists.mysql.com/)