File system and ACL support

Special file systems contain dynamic information that is generated by the operating system; they contain no data or files. The UNIX and Linux® clients ignore special file systems and their contents.

The stand-alone package LSCqfs

Special file systems include the following types:

• The /proc file system on most of the UNIX platforms
• The /dev/fd file system on Solaris
• The /dev/pts on Linux

With file systems where NFS V4 ACLs are defined and used (Solaris ZFS and AIX JFS2 V2), even if only the standard UNIX permissions or ACLs have changed (such as with the CHMOD command), the file or directory is fully backed up again. With other file systems, this type of change causes only an attribute update on the IBM Spectrum Protect server.

To process all other file systems, use the virtualmountpoint option to enable support for the following items:

• To back up, restore, archive, and retrieve file data
• For basic UNIX and Linux permissions
• For change, access, and modification time stamps, and the directory tree structure

No other file system specific attributes, such as the ACL, are valid. The file system type for such file systems is set to "UNKNOWN".

For example, if the /media/abc/DATA1 file system is not supported by the client, add the following statement to dsm.sys to back up or archive the data in this file system:

VIRTUALMOUNTPOINT /media/abc/DATA1

This support is only available if the file system can use basic POSIX system calls, such as read or write processing on your system.

Cross-platform backup and restore are not supported. For example, data backed up by an AIX client is not available for restore by a Windows client and vice versa.

Note: Data that is backed up or archived by the Mac OS X client cannot be restored by any other client. Additionally, the Mac OS X client cannot restore or retrieve data from any other client.

You can use the cross-file system type restore or retrieve method for ACL information if both the original file system and the destination file system support compatible ACLs. For example, on Solaris, the ACL information that is backed up from a VxFS file system is restored to a UFS file system because these file systems support compatible ACLs. The ACL information is not restored during cross-file system restore or retrieve operations if the original file system and the destination file system do not support ACLs,

The following restrictions apply to the QFS file system:

• Image backup is not supported on QFS file systems.
• The Solaris backup-archive client does not support the combination of QFS and SAM needed to archive files onto tertiary background storage, such as tapes. Instead, it recalls files from tape to disk automatically if it finds migrated files during a backup.
• A QFS file system contains two hidden system files and a system directory that cannot be backed up; and this is acceptable because a backup of these files is not needed. They contain internal data to manage the file system. The internal data is automatically excluded from a backup and is re-created automatically by the file system itself, if a restore of files in that file system is completed.

Incremental, selective, filelist back up, archive, restore, and retrieve processing of the Veritas file system and its ACLs on AIX are supported. Restore of a Veritas volume on a Logical Volume Manager volume (and vice versa) is allowed, provided both have the same file system type.

The following information pertains only to Mac OS X systems:

• On Mac OS X systems, the UFS and HFSX file systems are case-sensitive whereas the HFS+ file system is not case-sensitive but is case-preserving. Files that you back up from a UFS or HFSX file system (case-sensitive) might not be restored properly to an HFS+ file system (not case-sensitive) file system. For example, on a UFS file system, files Afile and afile are seen as different files. However, on an HFS+ file system the two files are seen as identical.
• On Mac OS X, if case-sensitive HFS+ or UFS file systems are used, it is important that the data from the HFSX or UFS file system is not backed up to an HFS+ file system on the IBM Spectrum® Protect server. Either a new name must be used on the system or the existing file space on the IBM Spectrum Protect server must be renamed. For example, consider a system that has a file system named /Volumes/fs2 and this system is repartitioned with a case-sensitive HFS+ file system. Either the /Volumes/fs2 file system on the IBM Spectrum Protect server must be renamed, or a new name must be used on the local system. If this renaming is not done, the HFSX case-sensitive data is mixed with the HFS+ case-insensitive data that is already stored on the IBM Spectrum Protect server.
• On Mac OS X, aliases and symbolic links are backed up. However, the client does not back up the data to which the symbolic links point.
• On Mac OS X, when files that are backed up from an HFS volume are restored to a UFS volume, the resource forks are not assigned to the correct owner. Correct this problem by using the chown command on the resource fork file to change the owner. The resource fork file stores structured data in a file.

On Linux on POWER® and Linux on System z®, you must install libacl.so for the client to back up ACLs.

Important: If you are running GPFS for AIX, GPFS for Linux x86_64, or GPFS for Linux on z Systems in a multinode cluster, and all nodes share a mounted GPFS file system, the client processes this file system as a local file system. The client backs up the file system on each node during an incremental backup. To avoid this, you can do one of the following things:

• Explicitly configure the domain statement in the client user-options file (dsm.opt) to list the file systems you want that node to back up.
• Set the exclude.fs option in the dsm.sys file to exclude the GPFS file system from backup services.

If the GPFS cluster contains different platforms, you must use backup-archive clients on only one platform to protect a single file system. Do not use backup-archive clients on more than one platform to protect a GPFS file system that is shared among more than one platform

For example, assume that a cluster contains nodes on AIX, Linux x86, and Linux zSeries systems. You can protect file system A with AIX backup-archive clients and protect file system B with Linux zSeries backup-archive clients. Or you can protect file system A and file system B with AIX backup-archive clients. If you protect file system A with an AIX backup-archive client, you must not protect file system A with a backup-archive client on any platform other than AIX.