TN 035: Hotbackup (Redundancy) Configuration

Owned by Admin
Oct 13, 2021
5 min read

A Dream Report runtime node can be configured as a redundant station, that runs in conjunction with the main runtime node.

There is no special configuration required for the main station.

The backup (redundant) node must run the exact copy of the Dream Report project which is running on the main station.

 

Configuration

To pair a backup node to the main node, in Dream Report Studio on the backup node, open the Hotbackup Configuration window from the Project menu: 

The Hotbackup Configuration section will open:

To set the local node as a backup for the main node, check the option "This node is working in a Hotbackup mode".

Then, specify the IP address or PC name (without "\\" - just a network PC name) of the PC running as the main station (Set the IP address or name of the PC where the main node is running). This field must contain a valid information and it can't be empty.

To test the actual connectivity to the main station, click the Test Connection button, and the Designer Studio will try to connect to the main node. If the test connection succeeds, the message box "Test connection succeeded" will pop up.  If test connection to the main station fails, the message box "Test connection failed" will pop up.

Hot-Backup connection check uses port 57034 on both the main and the backup stations sides. This port should normally be allowed by Windows or any other installed Firewall software when a user unblocks runtime during its first launch. But if connection test fails, check the Firewall for a proper port configuration.

Once you have defined this node as a backup, you have also to specify the Checkup rate. It must be a positive, non-zero number between 1 to 86400 – this is the time interval in seconds, that this local runtime manager will check the connection to the main runtime station.  A shorter checkup rate is recommended – typically, every 10 seconds.

Important Notes:

  1. Make sure that all paths, network shares and mapped drives, networked printers that are defined on, and used by the main node, exist on the backup node

  2. If Dream Report will run as a Windows service, ensure that the account under which the RTM (runtime) service runs has access to the networked shares, and the appropriate rights to the SQL database (if being used)

  3. Make sure that the backup node can access all configured data sources defined in the project’s communication drivers).  If any of the data sources being used are local to the main node (e.g., a local OPC server or HMI) then the same local data source(s) should exist and be configured identically on the backup node

  4. If security (User Authentication) is being used, ensure that any local Windows accounts that might be referenced in the main project exist on the backup machine

  5. If the Dream Report Web Portal is being used, make sure to also run the “Configure IIS” option on the backup node (please see additional Tip at the end of this document).

 

Runtime Functionality

If the "This node is working in a hotbackup mode" option is checked, then, when starting the runtime manager, it will try to connect to the runtime manager on the PC specified as the main node. If connection check succeeds, then the backup node will work in a standby mode. It will not record data into a database and will not generate reports, but will only periodically check connection with the main station every "checkup rate".  If the check from the backup node to the main node fails, then the backup node becomes active – i.e.,

  • It starts communicating with real-time data sources and starts logging data (if defined)

  • Generates reports on schedule or on event triggers

  • Performs all other configured runtime activities in the project (notifications, audit trails, FTP transfers, etc.)

  • It becomes the active DRWeb portal

Note that the backup node continues to periodically check for the status of the main node, at the specified Checkup rate.  If it successfully connects, the main node becomes active again, and the backup node will return to its “standby” mode.

 

Data Logging

If the Dream Report project is configured to log data into its internal database it can be done in two possible ways:

  1. One central (common) database into which both stations are recording the data according to the station’s state – i.e., only the active station will write the data into the database.  Best practice is to use a database located on a dedicated, high-availability database server, that both Dream Report main and back nodes can connect to.

  2. Local SQL database on each station where the synchronization between two databases has to be configured manually by the company’s database administrator.

 

Licensing

A Dream Report node running backup mode, requires a license with a special "Backup" license option. This license is paired with the “main” runtime license – i.e., it must have the exact license options, with the addition of the “backup” option.  A license with backup option allows users to use that license only on a backup node – if the project option "This node is working in a Hotbackup mode" is not checked on the node where this license is being used, the license will prevent Dream Report runtime from operating.  Please contact your Dream Report distributor/reseller for pricing and additional details.

 

Tip – Dream Report Web Portal

If web portal redirect from master to backup station is required (so that the portal users don’t have to know which DRWeb portal is active), it can be configured manually as follows:

  1. In Windows Explorer, open the main Web portal folder, normally located in the path C:\ODS\Dream Report\DR_Web_Portal

  2. Search for the Settings.config file and open it in a text editor like Notepad

  3. Add the following attribute to the file: <add key="backupUrl" value="http://backup_station_ip/DR_Web" />, where "backup_station_ip" corresponds to the IP address of the node where the backup project is running:

  4. Save and close "Settings.config" file

  5. Open Internet Information Services (IIS) Manager with administrative rights and restart IIS.

Important Note: By pressing "Configure IIS" button in Dream Report Designer Studio or in RMC, the web redirect to the backup station configuration will be erased.  If needed, keep a backup copy of this file.