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

Table C-1
File system type and operating system versions (continued)
VxFS 5.0.1
and 5.1
SP1,
HP-UX 11i
v3
VxFS 5.0,
HP-UX 11i
v3
VxFS 5.0,
HP-UX
11i v2 PI
VxFS 4.1,
HP-UX
11i v2 PI
VxFS
3.5.2,
HP-UX
11i v2 PI
VxFS 3.5,
HP-UX
11i v1
JFS 3.3,
HP-UX
11i v1
Disk Layout
YesYesYesYesNoNoNomkfs
Version 7
YesYesYesYesNoNoNo
Local
Mount
YesYesYesYesNoNoNo
Shared
Mount
YesYesYesYesNoNoNomkfs
Version 8
YesYesYesYesNoNoNo
Local
Mount
YesYesYesYesNoNoNo
Shared
Mount
VxFS Version 4 disk layout
The Version 4 disk layout allows the file system to scale easily to accommodate
large files and large file systems.
The original disk layouts divided up the file system space into allocation units
(AUs). The first AU started part way into the file system which caused potential
alignment problems depending on where the first AU started. Each allocation
unit also had its own summary, bitmaps, and data blocks. Because this AU
structural information was stored at the start of each AU, this also limited the
maximum size of an extent that could be allocated. By replacing the allocation
unit model of previous versions, the need for alignment of allocation units and
the restriction on extent sizes was removed.
The VxFS Version 4 disk layout divides the entire file system space into fixed size
allocation units. The first allocation unit starts at block zero and all allocation
units are a fixed length of 32K blocks. An exception may be the last AU, which
occupies whatever space remains at the end of the file system. Because the first
AU starts at block zero instead of part way through the file system as in previous
versions, there is no longer a need for explicit AU alignment or padding to be
added when creating a file system.
235Disk layout
VxFS Version 4 disk layout