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.