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

NAME

     ffs -- Berkeley fast file system

SYNOPSIS

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

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

DESCRIPTION

     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.

   Quotas
     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 metadata 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 command:

	       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 discretionary 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 default ACL for directories.	If you are using file system extended
     attributes, 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 automatically 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
	 retrieved from userland as well as from within the kernel; see extattrctl(8).

     options UFS_EXTATTR_AUTOSTART
	 If this option is defined, ffs will search for a .attribute subdirectory 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 indirect 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.)

SEE ALSO

     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