1 .\" Copyright (c) 2007 The DragonFly Project. All rights reserved.
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 $
39 .Nd construct a new HAMMER file system
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 filesystems are designed for large storage systems, up to 1 Exabyte, and
85 will not operate efficiently on small storage systems.
86 The minimum recommended filesystem size is 50GB.
88 must reserve 500MB to 1GB of its storage for reblocking and UNDO.
89 In addition, HAMMER filesystems operating normally, with full history
90 retention and daily snapshots, do not immediately reclaim space when
92 A regular system maintenance cron job runs once a day to handle reclamation.
95 works best when the machine's normal workload would not otherwise fill
96 the filesystem up in the course of 60 days of operation.
98 The options are as follows:
99 .Bl -tag -width indent
103 file systems must be named and names should be unique on a
106 Specify a fixed area in which a boot related kernel and data can be stored.
109 is specified in bytes.
110 By default a boot area of approximately 4MB will be created.
112 Force the creation of a
114 file system with less than 100M UNDO FIFO.
115 This should not be used under normal circumstances.
117 Specify a fixed area which
119 may use as a memory log.
120 This area is currently unused.
123 is specified in bytes.
125 Specify the size of the fixed UNDO FIFO.
128 is specified in bytes.
129 By default 0.1% of the root
130 volume's size is used, with a reasonable minimum and a reasonable cap.
131 The UNDO FIFO is used to sequence meta-data out to the media for instant
134 Specify the HAMMER filesystem version to format.
137 formats the filesystem using the highest production version number
138 supported by the HAMMER VFS by checking the vfs.hammer.supported_version
140 If you need to maintain compatibility with an older version of HAMMER
141 you may specify the version with this option.
149 can be given with a suffix of
153 meaning kilo, mega, giga and tera.
154 Lower case can also be used for suffix.
156 .Bd -literal -offset indent
157 newfs_hammer -L Home /dev/ad0s1d
160 Create a file system named
165 Exit status is 0 on success and 1 on error.
176 utility first appeared in
179 .An Matthew Dillon Aq dillon@backplane.com