In a situation where files have been lost but the overall system remains healthy, the first line of defense for restoring files is to have previously used the FlashCopy function to create an image of the files. The FlashCopy function is available in SAN File System. The FlashCopy function provides a space-efficient image of the contents of part of the global namespace at a particular moment in time. The FlashCopy image contains read-only copies of the files in a specific fileset as they exist at a specific point in time.
The FlashCopy image is stored in a special subdirectory named .flashcopy under the fileset's root attach point. After you create a FlashCopy image of a fileset, you can use standard backup tools on the SAN File System client to back up the files by specifying the path to the FlashCopy image instead of the path to the actual files. This allows users and applications to continue working with the actual files while the backup occurs.
You can use the FlashCopy image to restore the entire fileset or restore a single file.
When using a file-based backup method other than the FlashCopy function, be aware of the associated file metadata backup, which includes all the permissions and extended attributes of the files. This file metadata for Windows-created files can only be backed up completely from a Windows client. Similarly, file metadata for UNIX® files can only be backed up completely from an UNIX client. Therefore, if it is important for you to preserve full file-attribute information, create separate filesets by primary allegiance. In other words, have certain filesets that only contain Windows-created files, and other filesets that only contain UNIX-created files. In this way, you can back up the filesets from the appropriate client operating system.