roles/mariadb: Remove innodb_buffer_pool_instances

This was deprecated in MariaDB 10.5. The setting is now ignored and
will be removed in a future version.

See: https://mariadb.com/kb/en/changes-improvements-in-mariadb-105/#innodb-removed-or-deprecated-variables

roles/mariadb/defaults/main.yml

@@ -15,10 +15,6 @@ aria_pagecache_buffer_size: 8M
 # default is 128M, but set to at least the size of your InnoDB data
 innodb_buffer_pool_size: 256M
 
-# Unless you have a pool size over 1GB, use a single instance
-# See: https://mariadb.com/kb/en/mariadb/xtradbinnodb-server-system-variables
-innodb_buffer_pool_instances: 1
-
 # Ansible 2.7.x with PyMySQL seems to default to TCP connection so we should
 # force it to use a Unix socket.
 # See: https://github.com/ansible/ansible/issues/47736

roles/mariadb/templates/my.cnf.j2

@@ -141,7 +141,6 @@ innodb_file_per_table	= 1
 innodb_open_files	= 400
 innodb_io_capacity	= 400
 innodb_flush_method	= O_DIRECT
-innodb_buffer_pool_instances = {{ innodb_buffer_pool_instances }}
 
 aria_pagecache_buffer_size = {{ aria_pagecache_buffer_size }}
 #