volfs(7)
NAME
volfs − Volume Management filesystem
DESCRIPTION
volfs is the Volume Management filesystem rooted at /vol.
All media names managed by Volume Management are contained in a file system rooted at /vol.
Media can be accessed in a logical manner (no association with a particular piece of hardware), or a physical manner (associated with a particular piece of hardware).
Logical names for media are referred to through /vol/dsk and /vol/rdsk. These represent block access to random access devices, and character access to random access devices respectively. The default permissions for /vol are mode=0555, owner=root, group=sys. The default permissions for /vol/dsk and /vol/rdsk are mode=01777, owner=root, group=sys.
The /vol/rdsk and /vol/dsk directories are mirrors of one another. Any change to one is reflected in the other immediately. The dev_t for a volume will be the same for both the block and character device.
Physical references to media are obtained through /vol/dev. This hierarchy reflects the structure of the /dev name space. The default permissions for all directories in the /vol/dev hierarchy are mode=0555, owner=root, group=sys.
mkdir(2), rmdir(2), unlink(2) (rm), symlink(2) (ln −s), link(2) (ln), and rename(2) (mv) are supported, subject to normal file and directory permissions.
The following system calls are not supported in the /vol filesystem: creat(2), only when creating a file, and mknod(2).
For more information on the location of media, see SunOS 5.1 Adding and Maintaining Devices and Drivers
Partitions
Some media supports the concept of a partition. If the label identifies partitions on the media, the name of the media will become a directory with partitions under it. Only valid partitions are represented. Partitions cannot be moved out of a directory.
Example: disk volume ’foo’ has 3 valid partitions: 0, 2, 5.
/vol/dsk/foo/s0, /vol/dsk/foo/s2, /vol/dsk/foo/s5,
/vol/rdsk/foo/s0, /vol/rdsk/foo/s2, /vol/rdsk/foo/s5
If a volume is relabeled to reflect different partitions, the name space changes to reflect the new partition layout.
A format program can check to see if there are others with the volume open and not allow the format to occur if it is. Volume Management, however, does not explicitly prevent the rewriting of a label while others have the volume open. If a partition of a volume is open, and the volume is relabeled to remove that partition, it will appear exactly as if the volume were missing. A notify event will be generated and the user may cancel the operation with volcancel(1), if desired.
SEE ALSO
SunOS 5.1 Routine System Administration Guide
SunOS 5.1 Adding and Maintaining Devices and Drivers
SunOS 5.2 — Last change: 23 Feb 1993