xref: /freebsd/sbin/mdmfs/mdmfs.8 (revision cc16dea626cf2fc80cde667ac4798065108e596c)
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2.\" Copyright (c) 2001 Dima Dorfman.
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26.\" $FreeBSD$
27.\"
28.Dd September 4, 2011
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 DLlMNPStUX
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 n Ar rotational-positions
51.Op Fl O Ar optimization
52.Op Fl o Ar mount-options
53.Op Fl p Ar permissions
54.Op Fl s Ar size
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 Ar rotational-positions
171The default number of rotational positions to distinguish.
172.It Fl O Ar optimization
173Select the optimization preference;
174valid choices are
175.Cm space
176and
177.Cm time ,
178which will optimize for minimum space fragmentation and
179minimum time spent allocating blocks,
180respectively.
181.It Fl o Ar mount-options
182Specify the mount options with which to mount the file system.
183See
184.Xr mount 8
185for more information.
186.It Fl P
187Preserve the existing file system;
188do not run
189.Xr newfs 8 .
190This only makes sense if
191.Fl F
192is specified to create a vnode-backed disk.
193.It Fl p Ar permissions
194Set the file (directory) permissions of the mount point
195.Ar mount-point
196to
197.Ar permissions .
198The
199.Ar permissions
200argument can be in any of the mode formats recognized by
201.Xr chmod 1 .
202If symbolic permissions are specified,
203the operation characters
204.Dq +
205and
206.Dq -
207are interpreted relative to the initial permissions of
208.Dq a=rwx .
209.It Fl S
210Do not enable soft-updates on the file system.
211.It Fl s Ar size
212Specify the size of the disk to create.
213This only makes sense if
214.Fl F
215is
216.Em not
217specified.
218That is,
219this will work for the default swap-backed
220.Pq Dv MD_SWAP
221disks,
222and the optional
223.Pq Fl M
224.Xr malloc 9
225backed disks
226.Pq Dv MD_MALLOC .
227.It Fl t
228Turn on the TRIM enable flag for
229.Xr newfs 8 .
230The
231.Xr md 4
232device supports the BIO_DELETE command, enabling the TRIM on created
233filesystem allows return of freed memory to the system pool.
234.It Fl U
235Enable soft-updates on the file system.
236This is the default, and is accepted only
237for compatibility.
238It is only really useful to negate the
239.Fl S
240flag, should such a need occur.
241.It Fl v Ar version
242Specify the UFS version number for use on the file system; it may be
243either
244.Dv 1
245or
246.Dv 2 .
247The default is derived from the default of the
248.Xr newfs 8
249command.
250.It Fl w Ar user : Ns Ar group
251Set the owner and group to
252.Ar user
253and
254.Ar group ,
255respectively.
256The arguments have the same semantics as with
257.Xr chown 8 ,
258but specifying just a
259.Ar user
260or just a
261.Ar group
262is not supported.
263.It Fl X
264Print what command will be run before running it, and
265other assorted debugging information.
266.El
267.Pp
268The
269.Fl F
270and
271.Fl s
272options are passed to
273.Xr mdconfig 8
274as
275.Fl f
276and
277.Fl s ,
278respectively.
279The
280.Fl a , b , c , d , e , f , i , m
281and
282.Fl n
283options are passed to
284.Xr newfs 8
285with the same letter;
286the
287.Fl O
288option is passed to
289.Xr newfs 8
290as
291.Fl o .
292The
293.Fl o
294option is passed to
295.Xr mount 8
296with the same letter.
297See the programs that the options are passed to for more information
298on their semantics.
299.Sh EXAMPLES
300Create and mount a 32 megabyte swap-backed file system on
301.Pa /tmp :
302.Pp
303.Dl "mdmfs -s 32m md /tmp"
304.Pp
305The same file system created as an entry in
306.Pa /etc/fstab :
307.Pp
308.Dl "md /tmp mfs rw,-s32m 2 0"
309.Pp
310Create and mount a 16 megabyte malloc-backed file system on
311.Pa /tmp
312using the
313.Pa /dev/md1
314device;
315furthermore,
316do not use soft-updates on it and mount it
317.Cm async :
318.Pp
319.Dl "mdmfs -M -S -o async -s 16m md1 /tmp"
320.Pp
321Create and mount a
322.Xr geom_uzip 4
323based compressed disk image:
324.Pp
325.Dl "mdmfs -P -F foo.uzip -oro md.uzip /tmp/"
326.Pp
327Mount the same image, specifying the
328.Pa /dev/md1
329device:
330.Pp
331.Dl "mdmfs -P -F foo.uzip -oro md1.uzip /tmp/"
332.Pp
333Configure a vnode-backed file system and mount its first partition,
334using automatic device numbering:
335.Pp
336.Dl "mdmfs -P -F foo.img mds1a /tmp/"
337.Sh COMPATIBILITY
338The
339.Nm
340utility, while designed to be compatible with
341.Xr mount_mfs 8 ,
342can be useful by itself.
343Since
344.Xr mount_mfs 8
345had some silly defaults, a
346.Dq compatibility
347mode is provided for the case where bug-to-bug compatibility is desired.
348.Pp
349Compatibility is enabled by starting
350.Nm
351with the name
352.Li mount_mfs
353or
354.Li mfs
355(as returned by
356.Xr getprogname 3 ) .
357In this mode, the following behavior, as done by
358.Xr mount_mfs 8 ,
359is duplicated:
360.Bl -bullet -offset indent
361.It
362The file mode of
363.Ar mount-point
364is set by default to
365.Li 01777
366as if
367.Fl p Ar 1777
368was given on the command line.
369.El
370.Sh SEE ALSO
371.Xr md 4 ,
372.Xr fstab 5 ,
373.Xr mdconfig 8 ,
374.Xr mount 8 ,
375.Xr newfs 8
376.Sh AUTHORS
377.An Dima Dorfman
378