Release 10.1A: OpenEdge Data Management:
Database Administration

Direct I/O (-directio)

Operating system and syntax	UNIX Windows	-directio
Use with	Maximum value	Minimum value	Single-user default	Multi-user default
CC, DBS	–	–	Not enabled	Not enabled

Use Direct I/O (-directio) to open all files in unbuffered mode, which enables the OpenEdge RDBMS to use an I/O technique that bypasses the operating system buffer pool and transfers data directly from a buffer to disk. This technique avoids the overhead of maintaining the operating system buffer pool and eliminates competition for operating system buffers between OpenEdge programs and other programs.

You might improve performance by using the direct I/O feature. To use direct I/O, use Blocks in Database Buffers (-B) to increase the size of the buffer pool, since OpenEdge database I/O will not pass through the operating system buffer pool. Also, decrease the size of the operating system buffer pool to compensate for the additional memory allocated to the database.

Note: Use asynchronous page writers (APWs). They improve database performance by performing overhead operations in the background.