1 .\" Copyright (c) 2001 Networks Associates Technology, Inc.
2 .\" All rights reserved.
4 .\" This software was developed for the FreeBSD Project by Chris
5 .\" Costello at Safeport Network Services and NAI Labs, the Security
6 .\" Research Division of Network Associates, Inc. under DARPA/SPAWAR
7 .\" contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
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19 .\" THIS SOFTWARE IS PROVIDED BY THE AUTHORS AND CONTRIBUTORS ``AS IS'' AND
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31 .\" $FreeBSD: src/share/man/man7/ffs.7,v 1.13 2005/07/23 15:09:27 markus Exp $
32 .\" $DragonFly: src/share/man/man5/ffs.5,v 1.2 2008/07/27 22:21:11 thomas Exp $
40 .Nd Berkeley fast file system
42 In the kernel configuration file:
45 .Cd "options SOFTUPDATES"
47 .Cd "options UFS_DIRHASH"
52 /dev/disk0a /mnt ufs rw 1 1
55 The Berkeley fast file system
56 provides facilities to store file system data onto a disk device.
58 has been optimized over the years
59 for speed and reliability
66 MIBs are defined for use with
68 .Bl -hang -width ".Va vfs.ffs.doreallocblk"
69 .It Va vfs.ffs.doasyncfree
70 Asynchronously write out modified i-node and indirect blocks
71 upon reallocating file system blocks to be contiguous.
73 .It Va vfs.ffs.doreallocblks
74 Enable support for the rearrangement of blocks
80 .It Cd "options QUOTA"
81 This option allows system administrators
82 to set limits on disk usage
84 Quotas can be used only on file systems
95 .It Cd "options SOFTUPDATES"
96 The soft updates feature tracks writes to the disk
97 and enforces metadata update dependencies
98 (e.g., updating free block maps)
99 to ensure that the file system remains consistent.
101 To enable soft updates on an
103 file system, use the following command:
105 .D1 Nm tunefs Fl n Cm enable Ar fs
108 can be either a mount point listed in
116 .Ss File Ownership Inheritance
118 .It Cd "options SUIDDIR"
119 For use in file sharing environments
120 on networks including
121 .Tn "Microsoft Windows"
123 .Tn "Apple Macintosh"
125 this option allows files on file systems
129 to inherit the ownership of its directory,
131 .Dq "if it's my directory, it must be my file."
133 .Ss Directory Hashing
135 .It Cd "options UFS_DIRHASH"
136 Implements a hash-based lookup scheme for directories
137 in order to speed up accesses to very large directories.
149 .%T "A Fast File System for UNIX"
150 .%J "ACM Transactions on Computer Systems"
158 .%T "Soft Updates: A Technique for Eliminating Most Synchronous Writes in the Fast Filesystem"
159 .%J "Proceedings of the Freenix Track at the 1999 Usenix Annual Technical Conference"