dsync,direct io

The directio and dsync parameters are mutually exclusive. If a device has dsync set to “true,” you cannot set
directio to “true” for this device. To enable directio for a device, you must first reset dsync to “false.”
Direct I/O is always the preferred way.
dsync only applies to operating system files (meaning that it has no effect on "raw" devices used as Sybase disk devices)

The directio and dsync parameters are mutually exclusive. If a device has dsync set to “true,” you cannot set
directio to “true” for this device. To enable directio for a device, you must first reset dsync to “false.”
Direct I/O is always the preferred way.
dsync only applies to operating system files (meaning that it has no effect on "raw" devices used as Sybase disk devices)