Veritas File System 4.1 Administrator's Guide (HP-UX 11i v3, February 2007)

Extent Attributes
Commands Related to Extent Attributes
Chapter 358
Failure to Preserve Extent Attributes
Whenever a file is copied, moved, or archived using commands that preserve extent attributes, there is
nevertheless the possibility of losing the attributes. Such a failure might occur for three reasons:
• The file system receiving a copied, moved, or restored file from an archive is not a VxFS type. Since
other file system types do not support the extent attributes of the VxFS file system, the attributes of the
source file are lost during the migration.
• The file system receiving a copied, moved, or restored file is a VxFS type but does not have enough free
space to satisfy the extent attributes. For example, consider a 50K file and a reservation of 1 MB. If the
target file system has 500K free, it could easily hold the file but fail to satisfy the reservation.
• The file system receiving a copied, moved, or restored file from an archive is a VxFS type but the
different block sizes of the source and target file system make extent attributes impossible to maintain.
For example, consider a source file system of block size 1024, a target file system of block size 4096,
and a file that has a fixed extent size of 3 blocks (3072 bytes). This fixed extent size adapts to the source
file system but cannot translate onto the target file system.
The same source and target file systems in the preceding example with a file carrying a fixed extent size
of 4 could preserve the attribute; a 4 block (4096 byte) extent on the source file system would translate
into a 1 block extent on the target.
On a system with mixed block sizes, a copy, move, or restoration operation may or may not succeed in
preserving attributes. It is recommended that the same block size be used for all file systems on a given
system.