Design and Implementation of a Transaction-Based Filesystem on FreeBSD

Transactional database management systems (DBMS's) have special data integrity requirements that standard filesystems such as the Berkeley Fast Filesystem do not address. This paper briefly describes the requirements a transactional DBMS makes of a transaction-based filesystem, then goes on to describe the design and implementation of such a filesystem, referred to as a block repository 1 , which is part of the SQRL DBMS project.

The implementation of SQRL's block repository is different than most traditional filesystems in that it is purposely implemented in user-land using raw devices and threads. Its performance is more tunable to the needs of transaction processing than would be the case if it were integrated into the kernel.