Implements configuring innodb_file_per_table (fixes: lp1418570)

config.yaml

@@ -60,3 +60,12 @@ options:
       order for this charm to function correctly, the privacy extension must be
       disabled and a non-temporary address must be configured/available on
       your network interface.
+  innodb-file-per-table:
+     type: boolean
+     default: True
+     description: | 
+       Turns on innodb_file_per_table option, which will make MySQL put each
+       InnoDB table into separate .idb file. Existing InnoDB tables will remain
+       in ibdata1 file - full dump/import is needed to get rid of large
+       ibdata1 file
+     

hooks/percona_hooks.py

@@ -109,7 +109,8 @@ def render_config(clustered=False, hosts=[], mysql_password=None):
         'clustered': clustered,
         'cluster_hosts': ",".join(hosts),
         'sst_method': 'xtrabackup',
-        'sst_password': mysql_password
+        'sst_password': mysql_password,
+        'innodb_file_per_table': config('innodb-file-per-table')
     }
 
     if config('prefer-ipv6'):

templates/my.cnf

@@ -33,6 +33,17 @@ innodb_locks_unsafe_for_binlog=1
 # This changes how InnoDB autoincrement locks are managed and is a requirement for Galera
 innodb_autoinc_lock_mode=2
 
+# This enables storing InnoDB tables in separate .ibd files. Note that, however
+# existing InnoDB tables will remain in ibdata file(s) unles OPTIMIZE is run 
+# on them. Still, the ibdata1 file will NOT shrink - a full dump/import of the
+# data is needed in order to get rid of large ibdata file.
+
+{% if innodb_file_per_table %} 
+innodb_file_per_table = 1
+{% else %}
+innodb_file_per_table = 0
+{% endif %}
+
 # Node #1 address
 wsrep_node_address={{ private_address }}