VERITAS File System 4.1 Administrator's Guide

Extent Attributes
Commands Related to Extent Attributes
Chapter 374
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.