HP JFS 3.3 and HP OnLineJFS 3.3 VERITAS File System 3.3 System Administrator's Guide

80 Chapter3
Extent Attributes
Commands Related to Extent Attributes
• The force keyword issues an error if attributes are lost and the file
is not relocated.
The ls command has an -e option, which prints the extent attributes
of the file.
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.