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3.\" This code is derived from software contributed to The DragonFly Project
4.\" by Matthew Dillon <dillon@backplane.com>
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33.Dd October 7, 2011
34.Dt NEWFS_HAMMER 8
35.Os
36.Sh NAME
37.Nm newfs_hammer
38.Nd construct a new HAMMER file system
39.Sh SYNOPSIS
40.Nm
41.Fl L Ar label
42.Op Fl \&Ef
43.Op Fl b Ar bootsize
44.Op Fl m Ar savesize
45.Op Fl u Ar undosize
46.Op Fl V Ar version
47.Ar special ...
48.Sh DESCRIPTION
49The
50.Nm
51utility creates a
52.Nm HAMMER
53file system on device(s)
54.Ar special .
55If multiple devices are specified a single
56.Nm HAMMER
57file system is created
58which spans all of them.
59Each
60.Ar special
61will constitute a volume which the
62.Nm HAMMER
63file system is built on.
64The first
65.Ar special
66specified becomes the
67.Ar root-volume .
68.Nm HAMMER
69file systems are sector-size agnostic, however the
70.Dx
71implementation requires the sector size to be no larger than 16K.
72.Nm HAMMER
73file systems start at a relative offset of 0 and may only be created
74under out-of-band disk labels
75.Po
76.Xr disklabel64 5
77or
78.Xr gpt 8
79labels
80.Pc ,
81or in
82.Xr disklabel32 5
83partitions which do not overlap the label area (have a starting sector
84greater than 16).
85.Pp
86.Nm HAMMER
87file systems are designed for large storage systems, up to 1 Exabyte, and
88will not operate efficiently on small storage systems.
89The minimum recommended file system size is 50GB.
90.Nm HAMMER
91must reserve 500MB to 1GB of its storage for reblocking and UNDO/REDO.
92In addition,
93.Nm HAMMER
94file systems operating normally, with full history
95retention and daily snapshots, do not immediately reclaim space when
96files are deleted.
97A regular system maintenance job runs once a day by
98.Xr periodic 8
99to handle reclamation.
100.Pp
101.Nm HAMMER
102works best when the machine's normal workload would not otherwise fill
103the file system up in the course of 60 days of operation.
104.Pp
105The options are as follows:
106.Bl -tag -width indent
107.It Fl L Ar label
108All
109.Nm HAMMER
110file systems must be named and names should be unique on a
111per-machine basis.
112.It Fl b Ar bootsize
113Specify a fixed area in which a boot related kernel and data can be stored.
114The
115.Ar bootsize
116is specified in bytes.
117By default a boot area of approximately 4MB will be created.
118.It Fl f
119Force operation.
120This is needed for the creation of a
121.Nm HAMMER
122file system less than 10GB size or
123with less than 500MB UNDO/REDO FIFO.
124This should not be used under normal circumstances.
125.It Fl E
126Use TRIM to erase the device's data before creating the file system.
127The underlying device must have the TRIM sysctl enabled.
128Only devices that support TRIM will have such a sysctl option
129.Va ( kern.cam.da.X.trim_enabled ) .
130.It Fl m Ar savesize
131Specify a fixed area which
132.Nm HAMMER
133may use as a memory log.
134This area is currently unused.
135The
136.Ar savesize
137is specified in bytes.
138.It Fl u Ar undosize
139Specify the size of the fixed UNDO/REDO FIFO.
140The
141.Ar undosize
142is specified in bytes.
143By default 0.1% of the root
144volume's size is used, with a reasonable minimum and a reasonable cap.
145The UNDO/REDO FIFO is used to sequence meta-data out to the media for
146instant crash recovery.
147.It Fl V Ar version
148Specify the
149.Nm HAMMER
150file system version to format.
151By default
152.Nm
153formats the file system using the highest production version number
154supported by the
155.Nm HAMMER
156VFS by checking the
157.Va vfs.hammer.supported_version
158sysctl.
159If you need to maintain compatibility with an older version of
160.Nm HAMMER
161you may specify the version with this option.
162.El
163.Pp
164The
165.Ar bootsize ,
166.Ar savesize
167and
168.Ar undosize
169must be given with a suffix of
170.Cm K , M , G
171or
172.Cm T
173meaning kilobyte, megabyte, gigabyte and terabyte.
174Lower case can also be used for suffix.
175.Sh EXAMPLES
176.Bd -literal -offset indent
177newfs_hammer -L Home /dev/ad0s1d
178.Ed
179.Pp
180Create a file system named
181.Sq Home
182on
183.Pa /dev/ad0s1d .
184.Sh DIAGNOSTICS
185Exit status is 0 on success and 1 on error.
186.Sh SEE ALSO
187.Xr disklabel32 5 ,
188.Xr disklabel64 5 ,
189.Xr HAMMER 5 ,
190.Xr fdisk 8 ,
191.Xr gpt 8 ,
192.Xr newfs 8
193.Sh HISTORY
194The
195.Nm
196utility first appeared in
197.Dx 1.11 .
198.Sh AUTHORS
199.An Matthew Dillon Aq Mt dillon@backplane.com
200