All rights reserved.
This software was developed for the FreeBSD Project by Chris
Costello at Safeport Network Services and NAI Labs, the Security
Research Division of Network Associates, Inc. under DARPA/SPAWAR
contract N66001-01-C-8035 ("CBOSS"), as part of the DARPA CHATS
research program.
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$FreeBSD: head/share/man/man7/ffs.7 88579 2001-12-28 17:10:13Z chris $
.Dd December 26, 2001 .Dt FFS 4 .Sh NAME .Nm ffs .Nd Berkeley fast file system .Sh SYNOPSIS .Cd options FFS .Cd options SOFTUPDATES .Sh DESCRIPTION The Berkeley fast file system provides facilities to store file system data onto a disk device. .Nm FFS has been optimized over the years for speed and reliability and is the basis for the .Xr ufs 4 file system.
p The .Dv SOFTUPDATES option is used to enable soft updates. The soft updates feature tracks writes to the disk and enforces metadata update dependancies (e.g. updating free block maps) to ensure that the file system remains consistent. To enable this feature, add the following to your kernel configuration file:
p .Dl Cd options SOFTUPDATES
p To enable soft updates on an .Em unmounted file system, use the following command:
p .Dl Ic tunefs -n enable Sy /foo
p .Dq Sy foo can be either a mount point (e.g.
a /usr ) , or a disk device (e.g.
p The following .Xr sysctl 8 MIBs are defined for use with .Nm FFS : l -hang -width "vfs.ffs.doreallocblk" t Em vfs.ffs.doasyncfree Asynchronously write out modified inode and indirect blocks upon reallocating file system blocks to be contiguous. (Default: 1.) t Em vfs.ffs.doreallocblks Enable support for the rearrangement of blocks to be contiguous. (Default: 1.) .El .Sh SEE ALSO .Xr ufs 4 , .Xr tunefs 8 .Rs .%A M. McKusick .%A W. Joy .%A S. Lefler .%A R. Fabry .%D August 1984 .%T "A Fast File System for UNIX" .%J "ACM Transactions on Computer Systems" .%N 2 .%V 3 .%P 181-197 .Re .Rs .%A M. McKusick .%D June 2000 .%T "Soft Updates: A Technique for Eliminating Most Synchronous Writes in the Fast Filesystem" .%J "Proceedings of the Freenix Track at the 1999 Usenix Annual Technical Conference" .%P 71-84 .Re