In previous releases of WebSphere Application Server, the transaction logs were stored as operating system files. In WebSphere Application Server Version 8.5.5, this remains the default configuration but you can, optionally, choose to store the transaction logs in a relational database. This configuration option is aimed at customers working in a high availability (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 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.
In WebSphere Application Server Version 8.5.5, you can use a similar facility, also aimed at customers working in a HA environment, to store the compensation recovery logs in a relational database. The WebSphere Application Server compensation service allows applications on disparate systems to coordinate activities that are more loosely coupled than atomic transactions. It stores information, in its own dedicated recovery logs, that is necessary to perform compensation after a system failure.