DBFS is architected for high throughput, parallel, asynchronous data access. DBFS is a multi process, multi thread program. Each module is executed as a separate process and each request is handled in a separate thread which is obtained from the module specific thread pool. The Inter process communication is carried out through TCP sockets communication for reliable message delivery.
Architectural Overview
The design goals of DBFS are scalability, reliability, high throughput and high concurrency. In order to maximize the CPU utilization, the different DBFS sub-systems are run as separate process in an independent JVM instance.
DBFS provides a very high degree of scalability and concurrency by supporting asynchronous, non-blocking I/O operations. The number of I/O requests served is very high as there is no synchronous blocking I/O calls to the underlying storage system.
DBFS provides reliability by providing a foolproof mechanism for storage integrity and consistency. The data delivered by the DBFS is consistent across multiple request threads and are reliably persisted in the underlying storage. The health of the overall DBFS system is monitored and a mechanism for failover is provided for transparent switching of the DBFS subsystems.
Components of DBFS
DBFS consists of three main sub-systems – DBFS Storage Engine, Transaction Management System and Recovery Management System. Each of these sub-systems has its own address space which is shared by all the components of a sub-system. Therefore, each of these sub-systems is run as a separate process and the components in the sub-system runs as a Java™ Thread inside the corresponding VM. The Inter process communication between these sub-systems is carried out through TCP/IP socket communication.
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