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FFS(5)                   DragonFly File Formats Manual                  FFS(5)


ffs, ufs - Berkeley fast file system


In the kernel configuration file: options FFS options QUOTA options SOFTUPDATES options SUIDDIR options UFS_DIRHASH In fstab(5): /dev/disk0a /mnt ufs rw 1 1


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 DragonFly file system for /boot. Quotas 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 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 command: 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/da0s0a). File Ownership Inheritance 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." Directory Hashing options UFS_DIRHASH Implements a hash-based lookup scheme for directories in order to speed up accesses to very large directories.


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.) vfs.ufs.dirhash_docheck Enable extra sanity tests. (Default: 0.) vfs.ufs.dirhash_mem Current dirhash memory usage. vfs.ufs.dirhash_maxmem Maximum allowed dirhash memory usage. vfs.ufs.dirhash_minsize Minimum directory size in bytes for which to use hashed lookup.


quota(1), edquota(8), sysctl(8) M. McKusick, W. Joy, S. Leffler, 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. DragonFly 6.1-DEVELOPMENT February 17, 2018 DragonFly 6.1-DEVELOPMENT

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