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NAME    [Toc]    [Back]

     ffs -- Berkeley fast file system

SYNOPSIS    [Toc]    [Back]

     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

DESCRIPTION    [Toc]    [Back]

     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    [Toc]    [Back]
     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    [Toc]    [Back]
     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

	       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    [Toc]    [Back]
     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    [Toc]    [Back]
     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    [Toc]    [Back]
     options UFS_DIRHASH
	 Implements a hash-based lookup scheme for directories in order to
	 speed up accesses to very large directories.

   Extended Attributes    [Toc]    [Back]
     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

	 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    [Toc]    [Back]

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

     M. McKusick, W. Joy, S. Lefler, 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.

FreeBSD 5.2.1		       December 26, 2001		 FreeBSD 5.2.1
[ Back ]
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