BDT - Bulk Data Transfer

Enhanced Definition

BDT, or Bulk Data Transfer, is a z/OS component designed to facilitate the high-volume, high-speed transfer of data between z/OS systems, or between z/OS and other systems. It primarily leverages the Job Entry Subsystem (JES) and Network Job Entry (NJE) facilities to move large data sets, spool files, and jobs across a network. Its main purpose is to ensure efficient and reliable movement of significant amounts of data in an enterprise computing environment.

Key Characteristics

- JES Integration: BDT is tightly integrated with JES2 and JES3, allowing it to manage the transfer of jobs, SYSOUT, and other spool data as part of the standard JES workflow.
- Network Job Entry (NJE) Support: It extends the capabilities of NJE, enabling the transfer of bulk data not just between JES systems but also between different types of systems that support BDT protocols.
- Large Data Volume Handling: Optimized for moving very large data sets, including sequential, partitioned, and VSAM files, making it suitable for mainframe-to-mainframe or mainframe-to-distributed system data exchange.
- Checkpoint/Restart: Provides checkpoint and restart capabilities for long-running transfers, ensuring data integrity and allowing transfers to resume from the point of failure without starting over.
- Security Features: Supports various security mechanisms, including RACF integration, to control access to transferred data and ensure secure communication channels.
- Protocol Flexibility: Historically relied on SNA/VTAM for communication but can also utilize TCP/IP for network connectivity, offering flexibility in network infrastructure.

Use Cases

- Inter-system Data Exchange: Transferring large production data sets, such as database backups or master files, between different z/OS LPARs or data centers for processing, backup, or disaster recovery.
- Report Distribution: Distributing voluminous reports (SYSOUT) generated on one z/OS system to other systems or remote locations for printing or further processing.
- Software Distribution: Moving system software updates, patches, or application binaries from a central development or distribution system to multiple target z/OS systems.
- Batch Data Movement: Automating the transfer of input files to a remote system for batch processing and then retrieving the processed output files back to the originating system.
- Distributed Application Integration: Facilitating the exchange of large data files between mainframe applications and distributed applications running on other platforms.

Related Concepts

BDT works in close conjunction with JES (Job Entry Subsystem) and NJE (Network Job Entry). JES manages the job queues and spool, while NJE provides the framework for transmitting jobs and SYSOUT between JES systems. BDT enhances NJE by focusing on the efficient and high-volume transfer of general-purpose data sets. It relies on underlying network protocols like VTAM (Virtual Telecommunications Access Method) and SNA (Systems Network Architecture), or increasingly TCP/IP, for the actual data transmission across the network.

Best Practices:

Optimize Network Configuration: Ensure that the underlying network infrastructure (VTAM, TCP/IP) is properly configured and tuned for optimal throughput to avoid bottlenecks during bulk transfers.
Monitor BDT Activity: Regularly monitor BDT queues, transfer status, and resource utilization using system commands (D BDT) and monitoring tools to identify and resolve issues proactively.
Implement Robust Security: Utilize RACF or equivalent security managers to define appropriate authorization for BDT users and resources, ensuring data confidentiality and integrity during transit.
Leverage Checkpoint/Restart: For critical and lengthy transfers, ensure checkpointing is enabled to allow for efficient recovery from network interruptions or system failures.
Schedule Transfers Strategically: Schedule large bulk data transfers during off-peak hours to minimize impact on online transaction processing (OLTP) systems and other critical workloads.