Veritas™ File System 5.0.1 Programmer's Reference Guide

Downgrading Veritas File System versions

In the future, the VxFS version on a particular system may need to be downgraded

from a newer VxFS release (for example, VxFS 6.0) to VxFS 5.0. This may happen

when a file system is migrated from one operating system using VxFS 6.0 to

another using VxFS 5.0. If the FCL file created by this future VxFS version is

Version 3 or 4, it can then be used (as is) by the VxFS 5.0 installation. Changes

will continue to be tracked in the same FCL.

However, if the FCL version is higher than 4, then the FCL can not be activated

and the calls to the API functions fail. In this case, the existing FCL file needs to

be removed using fcladm rm and re-activated with FCL Version 3 or 4.

Reverse path name lookup

The reverse path name lookup feature obtains the full path name of a file or

directory from the inode number of that file or directory. The inode number is

provided as an argument to the vxfs_inotopath_gen library function. See the

vxfs_inotopath_gen(3) online manual page for more information.

The reverse path name lookup feature can be useful for a variety of applications

including the following:

■ Clients of the VxFS file change log feature

■ Backup and restore utilities

■ Replication products

Typically, these applications store information by inode numbers because a path

name for a file or directory can be very long and the applications require an easy

method to obtain a path name.

Inodes

An inode is a unique identification number for each file in a file system. An inode

contains the data and metadata associated with that file, but does not include the

filenames to which the inode corresponds. It is therefore relatively difficult to

determine the name of a file from an inode number. The ncheck command provides

a mechanism for obtaining a filename from an inode identifier by scanning each

directory in the file system, but this process can take a long time. The VxFS reverse

path name lookup feature obtains path names relatively quickly.

Note: Because symbolic links do not constitute a path to the file, the reverse path

name lookup feature cannot track symbolic links to files.

File Change Log

Reverse path name lookup