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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 .\" $DragonFly: src/sbin/newfs_hammer/newfs_hammer.8,v 1.10 2008/07/27 16:47:19 thomas Exp $
34 .Dd September 28, 2009
39 .Nd construct a new HAMMER file system
54 file system on device(s)
56 If multiple devices are specified a single
58 file system is created
59 which spans all of them.
62 will constitute a volume which the
64 file system is built on.
66 file systems are sector-size agnostic, however the
68 implementation requires the sector size to be no larger than 16K.
70 file systems start at a relative offset of 0 and may only be created
71 under out-of-band disk labels
80 partitions which do not overlap the label area (have a starting sector
84 file systems are designed for large storage systems, up to 1 Exabyte, and
85 will not operate efficiently on small storage systems.
86 The minimum recommended file system size is 50GB.
88 must reserve 500MB to 1GB of its storage for reblocking and UNDO.
91 file systems operating normally, with full history
92 retention and daily snapshots, do not immediately reclaim space when
94 A regular system maintenance job runs once a day by
96 to handle reclamation.
99 works best when the machine's normal workload would not otherwise fill
100 the file system up in the course of 60 days of operation.
102 The options are as follows:
103 .Bl -tag -width indent
107 file systems must be named and names should be unique on a
110 Specify a fixed area in which a boot related kernel and data can be stored.
113 is specified in bytes.
114 By default a boot area of approximately 4MB will be created.
116 Force the creation of a
118 file system with less than 100MB UNDO FIFO.
119 This should not be used under normal circumstances.
121 Specify a fixed area which
123 may use as a memory log.
124 This area is currently unused.
127 is specified in bytes.
129 Specify the size of the fixed UNDO FIFO.
132 is specified in bytes.
133 By default 0.1% of the root
134 volume's size is used, with a reasonable minimum and a reasonable cap.
135 The UNDO FIFO is used to sequence meta-data out to the media for instant
140 file system version to format.
143 formats the file system using the highest production version number
147 .Va vfs.hammer.supported_version
149 If you need to maintain compatibility with an older version of
151 you may specify the version with this option.
159 can be given with a suffix of
163 meaning kilobyte, megabyte, gigabyte and terabyte.
164 Lower case can also be used for suffix.
166 .Bd -literal -offset indent
167 newfs_hammer -L Home /dev/ad0s1d
170 Create a file system named
175 Exit status is 0 on success and 1 on error.
186 utility first appeared in
189 .An Matthew Dillon Aq dillon@backplane.com