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FFS(7)		     BSD Miscellaneous Information Manual		FFS(7)

     ffs -- Berkeley fast file system

     In	the kernel configuration file:
     options FFS
     options QUOTA
     options SOFTUPDATES
     options SUIDDIR
     options UFS_ACL
     options UFS_DIRHASH
     options UFS_EXTATTR

     In	fstab(5):
     /dev/disk0a     /mnt ufs rw 1 1

     The Berkeley fast file system provides facilities to store	file system
     data onto a disk device.  ffs has been optimized over the years for speed
     and reliability and is the	default	FreeBSD	file system.

     options QUOTA
	 This option allows system administrators to set limits	on disk	usage
	 on a per-user basis.  Quotas can be used only on file systems mounted
	 with the quota	option;	see quota(1) and edquota(8).

   Soft	Updates
     options SOFTUPDATES
	 The soft updates feature tracks writes	to the disk and	enforces meta-
	 data update dependencies (e.g., updating free block maps) to ensure
	 that the file system remains consistent.

	 To enable soft	updates	on an unmounted	file system, use the following

	       tunefs -n enable	fs

	 fs can	be either a mount point	listed in fstab(5) (e.g., /usr), or a
	 disk device (e.g., /dev/da0a).

   File	Ownership Inheritance
     options SUIDDIR
	 For use in file sharing environments on networks including Microsoft
	 Windows and Apple Macintosh computers,	this option allows files on
	 file systems mounted with the suiddir option to inherit the ownership
	 of its	directory, i.e., "if it's my directory,	it must	be my file."

   Access Control Lists
     options UFS_ACL
	 Access	control	lists allow the	association of fine-grained discre-
	 tionary access	control	information with files and directories.	 This
	 option	requires the presence of the UFS_EXTATTR option, and it	is
	 recommended that UFS_EXTATTR_AUTOSTART	is included as well, so	that
	 ACLs are enabled atomically upon mounting the file system.

     In	order to enable	support	for ACLs, two extended attributes must be
     available in the EXTATTR_NAMESPACE_SYSTEM namespace: posix1e.acl_access,
     which holds the access ACL, and posix1e.acl_default, which	holds the de-
     fault ACL for directories.	 If you	are using file system extended at-
     tributes, the following commands may be used to allocate space for	and
     create the	necessary EA backing files for ACLs in the root	of each	file
     system.  In these examples, the root file system is used; see Extended
     Attributes	for more details.

	   mkdir -p /.attribute/system
	   cd /.attribute/system
	   extattrctl initattr -p / 388	posix1e.acl_access
	   extattrctl initattr -p / 388	posix1e.acl_default

     On	the next mount of the root file	system,	the attributes will be auto-
     matically started (if UFS_EXTATTR_AUTOSTART is included in	the kernel
     configuration), and ACLs will be enabled.

   Directory Hashing
     options UFS_DIRHASH
	 Implements a hash-based lookup	scheme for directories in order	to
	 speed up accesses to very large directories.

   Extended Attributes
     options UFS_EXTATTR
	 Extended attributes allow the association of additional arbitrary
	 metadata with files and directories, which can	be assigned and	re-
	 trieved from userland as well as from within the kernel; see

	 If this option	is defined, ffs	will search for	a .attribute subdirec-
	 tory of the file system root during the mount operation.  If found,
	 extended attribute support will be automatically started for that
	 file system.

     The following sysctl(8) MIBs are defined for use with ffs:

     vfs.ffs.doasyncfree   Asynchronously write	out modified i-node and	indi-
			   rect	blocks upon reallocating file system blocks to
			   be contiguous.  (Default: 1.)

     vfs.ffs.doreallocblks Enable support for the rearrangement	of blocks to
			   be contiguous.  (Default: 1.)

     quota(1), acl(3), extattr(3), edquota(8), extattrctl(8), sysctl(8)

     M.	McKusick, W. Joy, S. Leffler, and R. Fabry, "A Fast File System	for
     UNIX", ACM	Transactions on	Computer Systems, 2, 3,	181-197, August	1984.

     M.	McKusick, "Soft	Updates: A Technique for Eliminating Most Synchronous
     Writes in the Fast	Filesystem", Proceedings of the	Freenix	Track at the
     1999 Usenix Annual	Technical Conference, 71-84, June 2000.

BSD			       December	26, 2001			   BSD


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