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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31 .\" $FreeBSD: src/share/man/man7/ffs.7,v 1.13 2005/07/23 15:09:27 markus Exp $
39 .Nd Berkeley fast file system
41 In the kernel configuration file:
44 .Cd "options SOFTUPDATES"
46 .Cd "options UFS_DIRHASH"
51 /dev/disk0a /mnt ufs rw 1 1
54 The Berkeley fast file system
55 provides facilities to store file system data onto a disk device.
57 has been optimized over the years
58 for speed and reliability
65 .It Cd "options QUOTA"
66 This option allows system administrators
67 to set limits on disk usage
69 Quotas can be used only on file systems
80 .It Cd "options SOFTUPDATES"
81 The soft updates feature tracks writes to the disk
82 and enforces metadata update dependencies
83 (e.g., updating free block maps)
84 to ensure that the file system remains consistent.
86 To enable soft updates on an
88 file system, use the following command:
90 .D1 Nm tunefs Fl n Cm enable Ar fs
93 can be either a mount point listed in
101 .Ss File Ownership Inheritance
103 .It Cd "options SUIDDIR"
104 For use in file sharing environments
105 on networks including
106 .Tn "Microsoft Windows"
108 .Tn "Apple Macintosh"
110 this option allows files on file systems
114 to inherit the ownership of its directory,
116 .Dq "if it's my directory, it must be my file."
118 .Ss Directory Hashing
120 .It Cd "options UFS_DIRHASH"
121 Implements a hash-based lookup scheme for directories
122 in order to speed up accesses to very large directories.
127 MIBs are defined for use with
129 .Bl -hang -width ".Va vfs.ufs.dirhash_docheck"
130 .It Va vfs.ffs.doasyncfree
131 Asynchronously write out modified i-node and indirect blocks
132 upon reallocating file system blocks to be contiguous.
134 .It Va vfs.ffs.doreallocblks
135 Enable support for the rearrangement of blocks
138 .It Va vfs.ufs.dirhash_docheck
139 Enable extra sanity tests.
141 .It Va vfs.ufs.dirhash_mem
142 Current dirhash memory usage.
143 .It Va vfs.ufs.dirhash_maxmem
144 Maximum allowed dirhash memory usage.
145 .It Va vfs.ufs.dirhash_minsize
146 Minimum directory size in bytes for which to use hashed lookup.
158 .%T "A Fast File System for UNIX"
159 .%J "ACM Transactions on Computer Systems"
167 .%T "Soft Updates: A Technique for Eliminating Most Synchronous Writes in the Fast Filesystem"
168 .%J "Proceedings of the Freenix Track at the 1999 Usenix Annual Technical Conference"