xref: /freebsd/sbin/mdmfs/mdmfs.8 (revision 49dae58b287906be26f56ba3e3dc693c3ba8cf37)
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2.\" Copyright (c) 2001 Dima Dorfman.
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26.\" $FreeBSD$
27.\"
28.Dd March 9, 2016
29.Dt MDMFS 8
30.Os
31.Sh NAME
32.Nm mdmfs ,
33.Nm mount_mfs
34.Nd configure and mount an in-memory file system using the
35.Xr md 4
36driver
37.Sh SYNOPSIS
38.Nm
39.Op Fl DLlMNnPStTUX
40.Op Fl a Ar maxcontig
41.Op Fl b Ar block-size
42.Op Fl c Ar blocks-per-cylinder-group
43.Op Fl d Ar max-extent-size
44.Op Fl E Ar path-mdconfig
45.Op Fl e Ar maxbpg
46.Op Fl F Ar file
47.Op Fl f Ar frag-size
48.Op Fl i Ar bytes
49.Op Fl m Ar percent-free
50.Op Fl O Ar optimization
51.Op Fl o Ar mount-options
52.Op Fl p Ar permissions
53.Op Fl s Ar size
54.Op Fl T Ar fstype
55.Op Fl v Ar version
56.Op Fl w Ar user : Ns Ar group
57.Ar md-device
58.Ar mount-point
59.Sh DESCRIPTION
60The
61.Nm
62utility is designed to be a work-alike and look-alike of the deprecated
63.Xr mount_mfs 8 .
64The end result is essentially the same,
65but is accomplished in a completely different way.
66The
67.Nm
68utility configures an
69.Xr md 4
70disk using
71.Xr mdconfig 8 ,
72puts a UFS file system on it (unless
73.Fl P
74was specified) using
75.Xr newfs 8 ,
76and mounts it using
77.Xr mount 8 .
78It can handle
79.Xr geom_uzip 4
80compressed disk images, as long as the kernel supports this GEOM class.
81All the command line options are passed to the appropriate program
82at the appropriate stage in order to achieve the desired effect.
83.Pp
84By default,
85.Nm
86creates a swap-based
87.Pq Dv MD_SWAP
88disk with soft-updates enabled
89and mounts it on
90.Ar mount-point .
91It uses the
92.Xr md 4
93device specified by
94.Ar md-device .
95If
96.Ar md-device
97is
98.Ql md
99(no unit number),
100it will use
101.Xr md 4 Ns 's
102auto-unit feature to automatically select an unused device.
103Unless otherwise specified with one of the options below,
104it uses the default arguments to all the helper programs.
105.Pp
106The following options are available.
107Where possible,
108the option letter matches the one used by
109.Xr mount_mfs 8
110for the same thing.
111.Bl -tag -width indent
112.It Fl a Ar maxcontig
113Specify the maximum number of contiguous blocks that will be laid
114out before forcing a rotational delay
115(see the
116.Fl d
117option).
118.It Fl b Ar block-size
119The block size of the file system, in bytes.
120.It Fl c Ar blocks-per-cylinder-group
121The number of blocks per cylinder group in the file system.
122.It Fl D
123If not using auto-unit,
124do not run
125.Xr mdconfig 8
126to try to detach the unit before attaching it.
127.It Fl d Ar max-extent-size
128The file system may choose to store large files using extents.
129This parameter specifies the largest extent size that may be
130used.  It is presently limited to its default value which is 16
131times the file system blocksize.
132.It Fl E Ar path-mdconfig
133Use
134.Ar path-mdconfig
135as a location of the
136.Xr mdconfig 8
137utility.
138.It Fl e Ar maxbpg
139Indicate the maximum number of blocks any single file can allocate
140out of a cylinder group before it is forced to begin allocating
141blocks from another cylinder group.
142.It Fl F Ar file
143Create a vnode-backed
144.Pq Dv MD_VNODE
145memory disk backed by
146.Ar file .
147.It Fl f Ar frag-size
148The fragment size of the file system in bytes.
149.It Fl i Ar bytes
150Number of bytes per inode.
151.It Fl l
152Enable multilabel MAC on the new file system.
153.It Fl L
154Show the output of the helper programs.
155By default,
156it is sent to
157.Pa /dev/null .
158.It Fl M
159Create a
160.Xr malloc 9
161backed disk
162.Pq Dv MD_MALLOC
163instead of a swap-backed disk.
164.It Fl m Ar percent-free
165The percentage of space reserved for the superuser.
166.It Fl N
167Do not actually run the helper programs.
168This is most useful in conjunction with
169.Fl X .
170.It Fl n
171Do not create a
172.Pa .snap
173directory on the new file system.
174.It Fl O Ar optimization
175Select the optimization preference;
176valid choices are
177.Cm space
178and
179.Cm time ,
180which will optimize for minimum space fragmentation and
181minimum time spent allocating blocks,
182respectively.
183.It Fl o Ar mount-options
184Specify the mount options with which to mount the file system.
185See
186.Xr mount 8
187for more information.
188.It Fl P
189Preserve the existing file system;
190do not run
191.Xr newfs 8 .
192This only makes sense if
193.Fl F
194is specified to create a vnode-backed disk.
195.It Fl p Ar permissions
196Set the file (directory) permissions of the mount point
197.Ar mount-point
198to
199.Ar permissions .
200The
201.Ar permissions
202argument can be in any of the mode formats recognized by
203.Xr chmod 1 .
204If symbolic permissions are specified,
205the operation characters
206.Dq +
207and
208.Dq -
209are interpreted relative to the initial permissions of
210.Dq a=rwx .
211.It Fl S
212Do not enable soft-updates on the file system.
213.It Fl s Ar size
214Specify the size of the disk to create.
215This only makes sense if
216.Fl F
217is
218.Em not
219specified.
220That is,
221this will work for the default swap-backed
222.Pq Dv MD_SWAP
223disks,
224and the optional
225.Pq Fl M
226.Xr malloc 9
227backed disks
228.Pq Dv MD_MALLOC .
229.It Fl t
230Turn on the TRIM enable flag for
231.Xr newfs 8 .
232When used with a file system that issue BIO_DELETE bio requests,
233.Xr md 4
234returns deleted blocks to the system memory pool.
235.It Fl T Ar fstype
236Specify a file system type for a vnode-backed memory disk.
237Any file system supported by
238.Xr mount 8
239command can be specified.
240This option only makes sense when
241.Fl F
242and
243.Fl P
244are used.
245.It Fl U
246Enable soft-updates on the file system.
247This is the default, and is accepted only
248for compatibility.
249It is only really useful to negate the
250.Fl S
251flag, should such a need occur.
252.It Fl v Ar version
253Specify the UFS version number for use on the file system; it may be
254either
255.Dv 1
256or
257.Dv 2 .
258The default is derived from the default of the
259.Xr newfs 8
260command.
261.It Fl w Ar user : Ns Ar group
262Set the owner and group to
263.Ar user
264and
265.Ar group ,
266respectively.
267The arguments have the same semantics as with
268.Xr chown 8 ,
269but specifying just a
270.Ar user
271or just a
272.Ar group
273is not supported.
274.It Fl X
275Print what command will be run before running it, and
276other assorted debugging information.
277.El
278.Pp
279The
280.Fl F
281and
282.Fl s
283options are passed to
284.Xr mdconfig 8
285as
286.Fl f
287and
288.Fl s ,
289respectively.
290The
291.Fl a , b , c , d , e , f , i , m
292and
293.Fl n
294options are passed to
295.Xr newfs 8
296with the same letter.
297The
298.Fl O
299option is passed to
300.Xr newfs 8
301as
302.Fl o .
303The
304.Fl o
305option is passed to
306.Xr mount 8
307with the same letter.
308The
309.Fl T
310option is passed to
311.Xr mount 8
312as
313.Fl t .
314See the programs that the options are passed to for more information
315on their semantics.
316.Sh EXAMPLES
317Create and mount a 32 megabyte swap-backed file system on
318.Pa /tmp :
319.Pp
320.Dl "mdmfs -s 32m md /tmp"
321.Pp
322The same file system created as an entry in
323.Pa /etc/fstab :
324.Pp
325.Dl "md /tmp mfs rw,-s32m 2 0"
326.Pp
327Create and mount a 16 megabyte malloc-backed file system on
328.Pa /tmp
329using the
330.Pa /dev/md1
331device;
332furthermore,
333do not use soft-updates on it and mount it
334.Cm async :
335.Pp
336.Dl "mdmfs -M -S -o async -s 16m md1 /tmp"
337.Pp
338Create and mount a
339.Xr geom_uzip 4
340based compressed disk image:
341.Pp
342.Dl "mdmfs -P -F foo.uzip -oro md.uzip /tmp/"
343.Pp
344Mount the same image, specifying the
345.Pa /dev/md1
346device:
347.Pp
348.Dl "mdmfs -P -F foo.uzip -oro md1.uzip /tmp/"
349.Pp
350Configure a vnode-backed file system and mount its first partition,
351using automatic device numbering:
352.Pp
353.Dl "mdmfs -P -F foo.img mds1a /tmp/"
354.Pp
355Mount a vnode-backed cd9660 file system using automatic device numbering:
356.Pp
357.Dl "mdmfs -T cd9660 -P -F foo.iso md /tmp"
358.Sh COMPATIBILITY
359The
360.Nm
361utility, while designed to be compatible with
362.Xr mount_mfs 8 ,
363can be useful by itself.
364Since
365.Xr mount_mfs 8
366had some silly defaults, a
367.Dq compatibility
368mode is provided for the case where bug-to-bug compatibility is desired.
369.Pp
370Compatibility is enabled by starting
371.Nm
372with the name
373.Li mount_mfs
374or
375.Li mfs
376(as returned by
377.Xr getprogname 3 ) .
378In this mode, the following behavior, as done by
379.Xr mount_mfs 8 ,
380is duplicated:
381.Bl -bullet -offset indent
382.It
383The file mode of
384.Ar mount-point
385is set by default to
386.Li 01777
387as if
388.Fl p Ar 1777
389was given on the command line.
390.El
391.Sh SEE ALSO
392.Xr md 4 ,
393.Xr fstab 5 ,
394.Xr mdconfig 8 ,
395.Xr mount 8 ,
396.Xr newfs 8
397.Sh AUTHORS
398.An Dima Dorfman
399