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
64 .It Cd "options QUOTA"
65 This option allows system administrators
66 to set limits on disk usage
68 Quotas can be used only on file systems
79 .It Cd "options SOFTUPDATES"
80 The soft updates feature tracks writes to the disk
81 and enforces metadata update dependencies
82 (e.g., updating free block maps)
83 to ensure that the file system remains consistent.
85 To enable soft updates on an
87 file system, use the following command:
89 .D1 Nm tunefs Fl n Cm enable Ar fs
92 can be either a mount point listed in
100 .Ss File Ownership Inheritance
102 .It Cd "options SUIDDIR"
103 For use in file sharing environments
104 on networks including
105 .Tn "Microsoft Windows"
107 .Tn "Apple Macintosh"
109 this option allows files on file systems
113 to inherit the ownership of its directory,
115 .Dq "if it's my directory, it must be my file."
117 .Ss Directory Hashing
119 .It Cd "options UFS_DIRHASH"
120 Implements a hash-based lookup scheme for directories
121 in order to speed up accesses to very large directories.
126 MIBs are defined for use with
128 .Bl -hang -width ".Va vfs.ufs.dirhash_docheck"
129 .It Va vfs.ffs.doasyncfree
130 Asynchronously write out modified i-node and indirect blocks
131 upon reallocating file system blocks to be contiguous.
133 .It Va vfs.ffs.doreallocblks
134 Enable support for the rearrangement of blocks
137 .It Va vfs.ufs.dirhash_docheck
138 Enable extra sanity tests.
140 .It Va vfs.ufs.dirhash_mem
141 Current dirhash memory usage.
142 .It Va vfs.ufs.dirhash_maxmem
143 Maximum allowed dirhash memory usage.
144 .It Va vfs.ufs.dirhash_minsize
145 Minimum directory size in bytes for which to use hashed lookup.
157 .%T "A Fast File System for UNIX"
158 .%J "ACM Transactions on Computer Systems"
166 .%T "Soft Updates: A Technique for Eliminating Most Synchronous Writes in the Fast Filesystem"
167 .%J "Proceedings of the Freenix Track at the 1999 Usenix Annual Technical Conference"