enable hp posix async i/o

enable hp posix async i/o enables or disables asynchronous I/O on database devices created on on HP-UX 11.31 and later file systems.

Summary Information

Default value

0

Valid values

1 (enabled), 0 (disabled)

Status

Static

Display level

Comprehensive

Required role

System administrator

Configuration group

Disk I/O

You must first enable SAP ASE to use asynchronous I/O with the allow sql server async i/o configuration parameter.

The combination of these configuration parameters determines whether SAP ASE uses asynchronous or synchronous I/O for raw partitions and file systems:

enable hp posix async i/o

allow sql server async i/o = 0

allow sql server async i/o = 1

Set to 0

Synchronous I/O for file systems Synchronous I/O for raw devices

Synchronous I/O for file systems

Uses /dev/async asynchronous I/O for raw devices

Set to 1

Synchronous I/O for file systems Synchronous I/O for raw devices

POSIX asynchronous I/O for file systems

POSIX asynchronous I/O for raw devices

Note: enable hp posix async i/o improves performance when you allocate database devices on file systems, but may decrease performance on database devices that are allocated on raw devices.