About Veritas File System I/O

VxFS processes two basic types of file system I/O:

For sequential I/O, VxFS employs a read-ahead policy by default when the application is reading data. For writing, it allocates contiguous blocks if possible. In most cases, VxFS handles I/O that is sequential through buffered I/O. VxFS handles random or nonsequential I/O using direct I/O without buffering.

VxFS provides a set of I/O cache advisories for use when accessing files.

See the Veritas File System Programmer's Reference Guide.

See the vxfsio(7) manual page.