Replication Process

Replication consists of two separate steps:

1. Writing a data update to the replication queue (creating a replication entry). The process that writes to the replication queue is run before any data changes are committed to the database. If the data change cannot be written to the replication queue – usually because the replication queue file has exceeded the maximum size allowed – the data change will not be committed to the database.

   

   Figure: Writing to the replication queue

2. Sending a replication entry to another OneSpan Authentication Server Appliance instance.

   

   Figure: Sending replication queue entry

Replication monitoring

Replication operations record dedicated audit messages in the following circumstances:

• A connection succeed or failed.
• A replication entry was sent successfully.
• A replication entry could not be sent.
• A replication entry was received and the receiving server returned a data update success message.
• A replication entry was received and the receiving server returned a data update failure message.

The OneSpan Authentication Server Administration Web Interface provides a Replication Status page. This page allows you to verify the current replication status for a specific OneSpan Authentication Server Appliance instance. It also includes the number of entries currently in the replication queue.

Forwarding replication entries

Replication forwarding is required and activated automatically where more than two OneSpan Authentication Server Appliance instances are replicating.

The ID of the source OneSpan Authentication Server Appliance instance and the target OneSpan Authentication Server Appliance instance(s) are added to the replication entry. This allows the receiving OneSpan Authentication Server Appliance instance to verify which other OneSpan Authentication Server Appliance instance the replication entry has already been sent. It will forward the entry only to those OneSpan Authentication Server Appliance instances not listed.

Multiple changes to a single data record

The replication method used by OneSpan Authentication Server Appliance involves replication of entire records, for example all settings of a specific user account, rather than an individual user account setting, such as the password. This means that data clashes can occur when a single record is updated at the same time from different sources. If this occurs, the later change is written to the database and earlier changes are ignored.