Storing transaction logs in a relational database
You can choose to store your Liberty transaction logs in a relational database rather than as operating system files. In the WebSphere® Application Server traditional, this feature provides high availability (HA) support without having to use a shared file system.
About this task
The WebSphere Application Server transaction service writes information to a transaction log for every global transaction that involves two or more resources, or that is distributed across multiple servers. These transactions are started or stopped either by applications or by the container in which they are deployed. The transaction service maintains transaction logs to ensure the integrity of transactions. Information is written to the transaction logs in the prepare phase of a distributed transaction, so that if a WebSphere Application Server with active transactions restarts after a failure, the transaction service is able to use the logs to replay any indoubt transactions. This allows the overall system to be brought back to a consistent state.
In previous releases of WebSphere Application Server, the transaction logs were stored as operating system files. In WebSphere Application Server Version 8.5.5 and later, this remains the default configuration but you can choose to store the transaction logs in a relational database management system (RDBMS). This configuration option is aimed at customers that work in an HA environment. In previous releases of WebSphere Application Server, HA transaction support required the use of a shared file system to host the transaction logs, such as an NFSv4-mounted network-attached storage (NAS) or a storage area network (SAN). This new feature allows customers, particularly those customers with an investment in HA database technology, to use their HA database as a shared repository for the transaction logs, as an alternative to using a shared file system.
By default, Liberty transaction logs are stored in operating system files. However, for compatibility with the WebSphere Application Server traditional, and for evaluation and testing purposes, you can configure the transaction logs to be stored in an RDBMS. You can use any database type that is supported by Liberty.
Procedure
To configure the Liberty transaction logs to be stored in an RDBMS, complete the following steps: