Veritas™ File System 5.0.1 Administrator's Guide

File placement policies and extending files
In a VxFS file system with an active file placement policy, the placement class on
whose volume a file resides is part of its metadata, and is attached when it is
created and updated when it is relocated. When an application extends a file, VxFS
allocates the incremental space on the volume occupied by the file if possible. If
not possible, VxFS allocates the space on another volume in the same placement
class. For example, if a file is created on a tier1 volume and later relocated to a
tier2 volume, extensions to the file that occur before the relocation have space
allocated on a tier1 volume, while those occurring after to the relocation have
their space allocated on tier2 volumes. When a file is relocated, all of its allocated
space, including the space acquired by extension, is relocated to tier2 volumes
in this case.
179Dynamic Storage Tiering
File placement policies and extending files