man newfs_hammer(8) - construct a new HAMMER file system

NAME

newfs_hammer - construct a new HAMMER file system

SYNOPSIS

newfs_hammer -L label [-b bootsize] [-f] [-m savesize] [-u undosize] special ...

DESCRIPTION

The newfs_hammer utility creates a HAMMER file system on device special. If multiple devices are specified a single HAMMER file system is created which spans all of them. Each special will constitute a volume which the HAMMER file system is built on. HAMMER file systems are sector-size agnostic, however the DragonFly implementation requires the sector size to be no larger than 16K. HAMMER file systems start at a relative offset of 0 and may only be created under out-of-band disk labels (disklabel64(5) or gpt(8) labels), or in disklabel(5) partitions which do not overlap the label area.

The options are as follows:

-L label

All HAMMER file systems must be named and names should be unique on a per-machine basis.

-b bootsize

Specify a fixed area in which a boot related kernel and data can be stored. The bootsize is specified in bytes. By default a boot area of approximately 4MB will be created.

-f

Force the creation of a HAMMER file system with less than 100M UNDO FIFO. This should not be used under normal circumstances.

-m savesize

Specify a fixed area which HAMMER may use as a memory log. This area is currently unused. The savesize is specified in bytes.

-u undosize

Specify the size of the fixed UNDO FIFO. The undosize is specified in bytes. By default 0.1% of the root volume's size is used, with a reasonable minimum and a reasonable cap. The UNDO FIFO is used to sequence meta-data out to the media for instant crash recovery.

The bootsize, savesize and undosize can be given with a suffix of K, M, G or T meaning kilo, mega, giga and tera. Lower case can also be used for suffix.

EXAMPLES

newfs_hammer -L Home /dev/ad0s1d

Create a file system named `Home' on /dev/ad0s1d.

DIAGNOSTICS

Exit status is 0 on success and 1 on error.

SEE ALSO

HAMMER(5), disklabel(5), disklabel64(5), fdisk(8), gpt(8), newfs(8)

HISTORY

The newfs_hammer utility first appeared in DragonFly 1.11.

AUTHORS

Matthew Dillon <dillon@backplane.com>