jBASE Distributed Locking Service
Although jBASE applications have been successfully deployed over Multiple Applications Servers, certain idiosyncrasies related to operating systems, performance and recovery of file locks over networked file systems have prompted the requirement to provide an alternative lock strategy for Multiple Application Server deployment. As such, the jBASE Distributed Lock Service is now offered as an alternative mechanism to the networked file system by which locks can be propagate between servers.
The Distributed lock service simply extends the existing lock mechanisms already available within jBASE by the provision of a distributed lock interface. It can be deployed as a service executing on a dedicated server or, as is more likely, deployed on one or two of the Application Servers in the Multiple Application Server configuration.
The Distributed lock service is provided via a daemon process
executing on Linux/Unix systems or as an installable service for
the Windows platform. It can be initiated using either the lower
case form of the executable, 'jdls', or the jBASE capitalized
convention for process daemons, jDLS, (jBASE Distributed Lock
The Distributed lock service also supersedes the jRLA, (jBASE Record Lock Arbiter), which provided the shared memory lock mechanism for record locks. Linux/Unix system boot scripts should be modified to initialize the lock mechanism using the jDLS rather than the jRLA executable.
Client processes on the Application Servers are configured to connect to the distributed lock service in order to request a lock be taken, request the status of a lock or request locks be released. Once initialized the client remains connected to the distributed lock service for the remainder of the life of the client process, with all lock requests issued and acknowledged through the same connection.
For more information, download the jBASE Distributed Locking manual (633 KB).
Please note the Distributed lock service is provided as an integral component of the jBASE 4.1.5 release. It is not available on releases prior to jBASE 4.1.5.