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32 .Nd "control utility for journaled devices"
65 utility is used for journal configuration on the given GEOM provider.
66 The Journal and data may be stored on the same provider or on two separate
68 This is block level journaling, not file system level journaling, which means
69 everything gets logged, e.g.\& for file systems, it journals both data and
73 GEOM class can talk to file systems, which allows the use of
75 for file system journaling and to keep file systems in a consistent state.
76 At this time, only UFS file system is supported.
78 To configure journaling on the UFS file system using
80 one should first create a
90 flag which instructs UFS to cooperate with the
93 There are important differences in how journaled UFS works.
94 The most important one is that
98 system calls do not work as expected anymore.
99 To ensure that data is stored on the data provider, the
101 command should be used after calling
103 For the best performance possible, soft-updates should be disabled when
106 It is also safe and recommended to use the
113 is configured on top of
117 providers, it also keeps them in a consistent state, thus
118 automatic synchronization on power failure or system crash may be disabled
123 utility uses on-disk metadata, stored in the provider's last sector,
124 to store all needed information.
125 This could be a problem when an existing file system is converted to use
128 The first argument to
130 indicates an action to be performed:
131 .Bl -tag -width ".Cm status"
135 on the given provider(s).
136 If only one provider is given, both data and journal are stored on the same
138 If two providers are given, the first one will be used as data provider and the
139 second will be used as the journal provider.
141 Additional options include:
142 .Bl -tag -width ".Fl s Ar jsize"
144 Checksum journal records.
146 May be used to convert an existing file system to use
148 but only if the journal will be configured on a separate provider and if the
149 last sector in the data provider is not used by the existing file system.
152 detects that the last sector is used, it will refuse to overwrite it
154 This behavior may be forced by using the
156 flag, which will force
158 to overwrite the last sector.
160 Hardcode provider names in metadata.
162 Specifies size of the journal if only one provider is used for both data and
164 The default is one gigabyte.
165 Size should be chosen based on provider's load, and not on its size.
166 It is not recommended to use
168 for small file systems (e.g.: only few gigabytes big).
171 Clear metadata on the given providers.
173 Stop the given provider.
175 Additional options include:
176 .Bl -tag -width ".Fl f"
178 Stop the given provider even if it is opened.
181 Trigger journal switch and enforce sending data to the data provider.
183 Dump metadata stored on the given providers.
198 Additional options include:
199 .Bl -tag -width ".Fl v"
204 Exit status is 0 on success, and 1 if the command fails.
208 based UFS file system and mount it:
209 .Bd -literal -offset indent
212 newfs -J /dev/da0.journal
213 mount -o async /dev/da0.journal /mnt
216 Configure journaling on an existing file system, but only if
218 allows this (i.e., if the last sector is not already used by the file system):
219 .Bd -literal -offset indent
221 gjournal label da0s1d da0s1e && \e
222 tunefs -J enable -n disable da01sd.journal && \e
223 mount -o async /dev/da0s1d.journal /mnt || \e
224 mount /dev/da0s1d /mnt
239 .An Pawel Jakub Dawidek Aq pjd@FreeBSD.org
241 Documentation for sysctls
242 .Va kern.geom.journal.*