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README.md

@@ -340,8 +340,8 @@ Type: `string`
 
 ### `mssql_ha_configure`
 
-Use the variables with the `mssql_ha_` prefix to configure SQL Server for high
-availability.
+Use variables with the 'mssql_ha_' prefix to configure an SQL Server Always On
+availability group to provide high availability.
 
 Set to `true` to configure for high availability. Setting to `false` does not
 remove configuration for high availability.
@@ -380,23 +380,28 @@ Type: `str`
 
 #### `mssql_ha_firewall_configure`
 
-Whether to configure firewall for high availability or not.
+Whether to open ports in the Linux firewall for an Always On availability
+group.
+
+The role uses the System Roles firewall role to manage the firewall,
+hence, only firewall implementations supported by the firewall role work.
 
 Default: `true`
 
 Type: `bool`
 
 #### `mssql_ha_listener_port`
 
-The TCP port to be used for high availability.
+The TCP port used to replicate data for an Always On availability group.
 
 Default: `5022`
 
 Type: `int`
 
 #### `mssql_ha_cert_name`
 
-The name of the certificate used for high availability configuration.
+The name of the certificate used to secure transactions between members of an
+Always On availability group.
 
 Default: `null`
 
@@ -420,7 +425,7 @@ Type: `str`
 
 #### `mssql_ha_reset_cert`
 
-Whether to reset certificates used for high availability or not.
+Whether to reset certificates used by an Always On availability group or not.
 
 Default: `false`
 
@@ -454,15 +459,24 @@ Type: `string`
 
 #### `mssql_ha_db_backup_path`
 
-The path to back up replicated database to.
+For SQL Server, any database participating in an Availability Group must be in a
+full recovery mode and have a valid log backup. The role uses this path to
+backup the database provided with `mssql_ha_db_name` prior to initiating
+replication within an Always On availability group.
+
+The role backs up the database provided with `mssql_ha_db_backup_path` if no
+back up newer than 3 hours exists.
 
 Default: `/var/opt/mssql/data/{{ mssql_ha_db_name }}.bak`
 
 Type: `string`
 
 #### `mssql_ha_login`
 
-The user to be created for pacemaker in SQL Server.
+The user created for pacemaker in SQL Server. This user is used by the SQL
+Server Pacemaker resource agent to connect to SQL Server to perform regular
+database health checks and manage state transitions from replica to primary when
+needed.
 
 Default: `null`
 
@@ -486,8 +500,11 @@ Type: `string`
 
 #### `mssql_ha_virtual_ip`
 
-A floating virtual IP address for accessing the master SQL Server node to be
-created in pacemaker.
+A floating virtual IP address for accessing the primary SQL Server node in an
+Always On availability group to be created in Pacemaker.
+
+In the event of a node failure, a synchronous replica is automatically promoted
+to primary and the address is assigned to this new node.
 
 Default: `null`