The directio Parameter

The directio parameter for disk init, disk reinit, and sp_deviceattr lets you bypass the operating system buffer cache and transfer SAP ASE data directly to disk.

directio performs I/O in the same manner as raw devices and provides the same performance benefit, but has the ease of use and manageability of file system devices.

By default, the directio option is set to true (on) for all platforms. directio and dsync are ignored for raw devices.

See the System Administration Guide, Volume 1.

Related concepts
The dsync Parameter