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33 .\" $DragonFly: src/sbin/hammer/hammer.8,v 1.10 2008/04/05 09:13:24 swildner Exp $
39 .Nd HAMMER file system utility
43 .Op Fl f Ar blkdev[:blkdev]*
50 utility provides miscellanious functions related to managing a HAMMER
53 The options are as follows:
54 .Bl -tag -width indent
58 Specify recursion for those commands which support it.
59 .It Fl f Ar blkdev[:blkdev]*
60 Specify the volumes making up a HAMMER filesystem.
62 When pruning a filesystem you can instruct HAMMER to create softlinks
63 to available snapshots.
65 Increase verboseness. May be specified multiple times.
67 Do not call sync() when running commands which sync() by default.
68 Timestamp commands such as 'hammer now' sync() by default. This also
69 disables any sleeps the timestamp commands would otherwise perform.
72 The commands are as follows:
73 .Bl -tag -width indent
75 Generate a timestamp suitable for use in the @@ filename extension,
76 representing right now.
79 is specified, this command will automatically sync() and
80 wait for the seconds hand to turn over (sleep for up to one second) prior
81 to generating a seconds-denominated timestamp.
83 Generate a full 64 bit timestamp.
86 is specified, this command will automatically sync(), but not sleep,
87 prior to generating the timestamp.
89 Generate a timestamp suitable for use in the @@ filename extension.
90 This command does not sync() or sleep and care should be taken if
91 generating timestamps for data which may not yet be synced to disk.
92 A time specification of
93 .Pf yyyymmdd Oo :hhmmss Oc Ns Op .fractional
94 specifies an exact as-of timestamp in local (not UTC) time.
95 Set the TZ environment variable prior to running
97 if you wish to specify the time by some other means.
101 command but generates a 64 bit timestamp.
102 .It Ar history Ar path
103 Show the modification history for a HAMMER file's inode and data.
104 .It Ar show Op vol_no[:clu_no]
105 Dump the B-Tree starting at the specified volume and cluster, or
106 at the root volume if not specified.
107 The B-Tree is dumped recursively if the
111 Dump the btree, record, large-data, and small-data blockmaps, showing
112 physical block assignments and free space percentages.
113 .It Ar namekey Ar filename
114 Generate a HAMMER 64 bit directory hash for the specified file name.
115 The low 32 bits are used as an iterator for hash collisions and will be
117 .It Ar namekey32 Ar filename
118 Generate the top 32 bits of a HAMMER 64 bit directory hash for the specified
120 .It Ar prune Ar filesystem Ar from Ar #{smhdMy} Ar to Ar #{smhdMy} Ar every Ar #{smhdMy}
121 .It Ar prune Ar filesystem Ar everything
122 .It Ar prune Ar filesystem Op Ar using Ar filename
123 Prune the filesystem, removing deleted records to free up physical disk
124 space. Specify a time range between the nearest modulo 0 boundary
125 and prune the tree to the specified granularity within that range.
127 The filesystem specification should be the root of any mounted HAMMER
128 filesystem. This command uses a filesystem ioctl to issue the pruning
129 operation. If you specify just the filesystem with no other parameters
130 all prune directives matching that filesystem in the /etc/hammer.conf file
131 will be used. If you specify a
133 file then those directives contained in the file matching
135 will be used. Multiple directives may be specified when extracting from
136 a file. The directives must be in the same format: "prune ....", in
137 ascending time order (per filesystem). Matching prune elements must not
138 have overlapping time specifications.
140 Both the "from" and the "to" value must be an integral multiple
141 of the "every" value, and the "to" value must be an integral multiple
142 of the "from" value. When you have multiple pruning rules you must
143 take care to ensure that the range being pruned does not overlap ranges
144 pruned later on, when the retained data is older. If they do the retained
145 data can wind up being destroyed. For example, if you prune your data
146 on a 30 minute granularity for the last 24 hours any later pruning must
147 use a granularity that is a multiple of 30 minutes. If you prune your
148 data on a 30 minute boundary, then a 1 day boundary in a later pruning (on
149 older data), then a pruning beyond that would have to be a multiple of
152 The "prune <filesystem> everything" command will remove all historical records
153 from the filesystem. The long keyword is designed to prevent accidental use.
154 This option is not recommended.
156 Example: "hammer prune /mnt from 1h to 1d every 30m"
160 Exit status is 0 on success and 1 on error.
166 utility first appeared in
169 .An Matthew Dillon Aq dillon@backplane.com