Veritas File System 5.1 SP1 Administrator"s Guide (5900-1499, April 2011)

To get an extent attribute's information
◆
Get the extent attribute information for the file file1:
# getext -F vxfs file1
file1: Bsize 1024 Reserve 36 Extent Size 3 align noextend
The file file1 has a block size of 1024 bytes, 36 blocks reserved, a fixed extent
size of 3 blocks, and all extents aligned to 3 block boundaries. The file size
cannot be increased after the current reservation is exhausted. Reservations
and fixed extent sizes are allocated in units of the file system block size.
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 one of the following 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.
Extent attributes
Commands related to extent attributes
68