ffs4

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 create a new file system with the soft updates enabled, use newfs(8) command:

newfs -U fs

fs can be either a mount point listed in fstab(5) (e.g., /usr), or a disk device (e.g., /dev/da0a).

It is possible to enable soft updates on an unmounted file system by using tunefs(8) command:

tunefs -n enable fs

Soft updates can also add journaling that reduces the time spent by fsck_ffs(8) cleaning up a filesystem after a crash from several minutes to a few seconds. The journal is placed in an inode named .sujournal, and is kept as a circular log of segments containing records that describe metadata operations.

To create a new file system with both the soft updates and soft updates journaling enabled, use the following command:

newfs -j fs

This runs tunefs(8) command after newfs(8) command with -U flag enabled. It is possible to enable soft updates journaling on an unmounted file system by using tunefs(8) command:

tunefs -j enable fs

This flag automatically enables the soft updates feature when it is not enabled. Note that this tunefs(8) command will fail if a file .sujournal already exists before enabling the soft updates journaling.

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.”

Access Control Lists

options UFS_ACL

Access control lists allow the association of fine-grained discretionary access control information with files and directories. This option requires the presence of the UFS_EXTATTR option, and it is recommended that UFS_EXTATTR_AUTOSTART is included as well, so that ACLs are enabled atomically upon mounting the file system.

In order to enable support for ACLs, two extended attributes must be available in the EXTATTR_NAMESPACE_SYSTEM namespace: posix1e.acl_access, which holds the access ACL, and posix1e.acl_default, which holds the default ACL for directories. If you are using file system extended attributes, the following commands may be used to allocate space for and create the necessary EA backing files for ACLs in the root of each file system. In these examples, the root file system is used; see Extended Attributes for more details.

mkdir -p /.attribute/system
cd /.attribute/system
extattrctl initattr -p / 388 posix1e.acl_access
extattrctl initattr -p / 388 posix1e.acl_default

On the next mount of the root file system, the attributes will be automatically started if UFS_EXTATTR_AUTOSTART is included in the kernel configuration, and ACLs will be enabled.

Directory Hashing

options UFS_DIRHASH

Implements a hash-based lookup scheme for directories in order to speed up accesses to very large directories.

Extended Attributes

options UFS_EXTATTR

Extended attributes allow the association of additional arbitrary metadata with files and directories, which can be assigned and retrieved from userland as well as from within the kernel; see extattrctl(8).

options UFS_EXTATTR_AUTOSTART

If this option is defined, ffs will search for a .attribute subdirectory of the file system root during the mount operation. If found, extended attribute support will be automatically started for that file system.

GEOM-based Journaling

options UFS_GJOURNAL

Implements a block level journaling of a UFS file system, which is for both data and metadata. To enable this, create a gjournal(8) GEOM provider for a block device by using the following command:

gjournal label da0

In this example, /dev/da0 is used as the target block device, and /dev/da0.journal is created. Then create a new file system by using newfs(8) with the block level journaling flag and mount it:

newfs -J /dev/da0.journal

mount -o async /dev/da0.journal /mnt

async option is not mandatory but recommended for better performance because the journaling guarantees the consistency of an async mount.

It is also possible to enable the block level journaling on an existing file system. To do so, use gjournal(8) utility to label the underlying block device and tunefs(8) utility to enable the block level journaling flag:

gjournal label da0

tunefs -J enable /dev/da0.journal

mount -o async /dev/da0.journal /mnt

Xr sysctl 8 MIBs

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.ffs.prttimechgs

Print a console message when timestamps for UFS1 filesystems are found to be in the future and are changed to be the present time. (Default: 0).