C.0 POSIX File System Support in OES Linux

This section provides information regarding the TSAFS support of POSIX-compliant file systems like ReiserFS, Ext2, Ext3, and XFS file systems on the OES Linux. These file systems are sometimes referred to in the document as non-NSS file systems.

POSIX-compliant means file systems that comply to the IEEE Std 1003.1 system interfaces. For more information, See Open Group Publications Web site.

The following table lists metadata that is backed up or restored to non-NSS file systems on OES Linux. The table uses the definition of metadata structure fields from the definition of the structure stat. (See man page stat(2) for more information)

Metadata	Description
st_mode	Mode of the file, including File types and File access permissions
st_nlink	Number of hard links to the file
st_uid	User ID of the file
st_gid	Group ID of the file
off_t	Size of the file
st_atime	Time of last access
st_mtime	Time of last data modification

File Types

Block special files
Character special files
Regular files
Directories
Symbolic links
Socket files

Additionally, TSAFS also backs up the following information for a file or directory (when applicable),

Symbolic link information
Data stream
Extended ACLs (POSIX Draft ACLs)
Extended attribute streams
File attributes on a Linux second extended file system

For more information on extended ACLs, see POSIX Access Control Lists on Linux.

For more information on file attributes on a Linux second extended file system, see man page chattr(1), installed by the RPM e2fsprogs.

POSIX Compliant File Systems Limitations

Backing up and restoring Extended Attributes is supported within the same file system, but restoration is not supported across different file systems.
During restoration, a nonroot user cannot overwrite the read-only files to the POSIX-complaint file systems, because write access is required for updating the files.