Applies To

• Microsoft Windows
• Linux

Answer

Direct Access (DAX) enables direct access to files stored in persistent memory or on a block device. Without DAX support in a file system, the page cache is generally used to buffer reads and writes to files, and requires an extra copy operation.

DAX removes the extra copy operation by performing reads and writes directly to the storage device. It is also used to provide the pages that are mapped into a user space by a call to mmap. For more information, refer to Direct Access for Files.