xref: /freebsd/sbin/mdmfs/mdmfs.8 (revision 2546665afcaf0d53dc2c7058fee96354b3680f5a)
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2.\" Copyright (c) 2001 Dima Dorfman.
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26.\" $FreeBSD$
27.\"
28.Dd February 26, 2004
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 DLlMNSUX
40.Op Fl a Ar maxcontig
41.Op Fl b Ar block-size
42.Op Fl c Ar cylinders
43.Op Fl d Ar rotdelay
44.Op Fl e Ar maxbpg
45.Op Fl F Ar file
46.Op Fl f Ar frag-size
47.Op Fl i Ar bytes
48.Op Fl m Ar percent-free
49.Op Fl n Ar rotational-positions
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 v Ar version
55.Op Fl w Ar user : Ns Ar group
56.Ar md-device
57.Ar mount-point
58.Nm
59.Fl C
60.Op Fl lNU
61.Op Fl a Ar maxcontig
62.Op Fl b Ar block-size
63.Op Fl c Ar cylinders
64.Op Fl d Ar rotdelay
65.Op Fl e Ar maxbpg
66.Op Fl F Ar file
67.Op Fl f Ar frag-size
68.Op Fl i Ar bytes
69.Op Fl m Ar percent-free
70.Op Fl n Ar rotational-positions
71.Op Fl O Ar optimization
72.Op Fl o Ar mount-options
73.Op Fl s Ar size
74.Op Fl v Ar version
75.Ar md-device
76.Ar mount-point
77.Sh DESCRIPTION
78The
79.Nm
80utility is designed to be a work-alike and look-alike of the deprecated
81.Xr mount_mfs 8 .
82The end result is essentially the same,
83but is accomplished in a completely different way.
84The
85.Nm
86utility configures an
87.Xr md 4
88disk using
89.Xr mdconfig 8 ,
90puts a UFS file system on it using
91.Xr newfs 8 ,
92and mounts it using
93.Xr mount 8 .
94All the command line options are passed to the appropriate program
95at the appropriate stage in order to achieve the desired effect.
96.Pp
97By default,
98.Nm
99creates a swap-based
100.Pq Dv MD_SWAP
101disk with soft-updates enabled
102and mounts it on
103.Ar mount-point .
104It uses the
105.Xr md 4
106device specified by
107.Ar md-device .
108If
109.Ar md-device
110is
111.Ql md
112(no unit number),
113it will use
114.Xr md 4 Ns 's
115auto-unit feature to automatically select an unused device.
116Unless otherwise specified with one of the options below,
117it uses the default arguments to all the helper programs.
118.Pp
119The following options are available.
120Where possible,
121the option letter matches the one used by
122.Xr mount_mfs 8
123for the same thing.
124.Bl -tag -width indent
125.It Fl a Ar maxcontig
126Specify the maximum number of contiguous blocks that will be laid
127out before forcing a rotational delay
128(see the
129.Fl d
130option).
131.It Fl b Ar block-size
132The block size of the file system, in bytes.
133.It Fl C
134Enable full compatibility mode with
135.Xr mount_mfs 8 .
136See the
137.Sx COMPATIBILITY
138section for more information.
139.It Fl c Ar cylinders
140The number of cylinders per cylinder group in the file system.
141.It Fl D
142If not using auto-unit,
143do not run
144.Xr mdconfig 8
145to try to detach the unit before attaching it.
146.It Fl d Ar rotdelay
147Specify the minimum time in milliseconds required to initiate another
148disk transfer on the same cylinder.
149Modern disks with read/write-behind achieve higher performance without
150this feature,
151so it is best to leave it at 0 milliseconds.
152.It Fl e Ar maxbpg
153Indicate the maximum number of blocks any single file can allocate
154out of a cylinder group before it is forced to begin allocating
155blocks from another cylinder group.
156.It Fl F Ar file
157Create a vnode-backed
158.Pq Dv MD_VNODE
159memory disk backed by
160.Ar file .
161.It Fl f Ar frag-size
162The fragment size of the file system in bytes.
163.It Fl i Ar bytes
164Number of bytes per inode.
165.It Fl l
166Enable multilabel MAC on the new file system.
167.It Fl L
168Show the output of the helper programs.
169By default,
170it is sent to
171.Pa /dev/null .
172.It Fl M
173Create a
174.Xr malloc 9
175backed disk
176.Pq Dv MD_MALLOC
177instead of a swap-backed disk.
178.It Fl m Ar percent-free
179The percentage of space reserved for the superuser.
180.It Fl N
181Do not actually run the helper programs.
182This is most useful in conjunction with
183.Fl X .
184.It Fl n Ar rotational-positions
185The default number of rotational positions to distinguish.
186.It Fl O Ar optimization
187Select the optimization preference;
188valid choices are
189.Cm space
190and
191.Cm time ,
192which will optimize for minimum space fragmentation and
193minimum time spent allocating blocks,
194respectively.
195.It Fl o Ar mount-options
196Specify the mount options with which to mount the file system.
197See
198.Xr mount 8
199for more information.
200.It Fl p Ar permissions
201Set the file (directory) permissions of the mount point
202.Ar mount-point
203to
204.Ar permissions .
205The
206.Ar permissions
207argument can be in any of the mode formats recognized by
208.Xr chmod 1 .
209If symbolic permissions are specified,
210the operation characters
211.Dq +
212and
213.Dq -
214are interpreted relative to the initial permissions of
215.Dq a=rwx .
216.It Fl S
217Do not enable soft-updates on the file system.
218.It Fl s Ar size
219Specify the size of the disk to create.
220This only makes sense if
221.Fl F
222is
223.Em not
224specified.
225That is,
226this will work for the default swap-backed
227.Pq Dv MD_SWAP
228disks,
229and the optional
230.Pq Fl M
231.Xr malloc 9
232backed disks
233.Pq Dv MD_MALLOC .
234.It Fl U
235Enable soft-updates on the file system.
236This is the default, even in compatibility mode, 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.Sh COMPATIBILITY
321The
322.Nm
323utility, while designed to be fully compatible with
324.Xr mount_mfs 8 ,
325can be useful by itself.
326Since
327.Xr mount_mfs 8
328had some silly defaults, a
329.Dq full compatibility
330mode is provided for the case where bug-to-bug compatibility is desired.
331.Pp
332Full compatibility is enabled with the
333.Fl C
334flag,
335or by starting
336.Nm
337with the name
338.Li mount_mfs
339or
340.Li mfs
341(as returned by
342.Xr getprogname 3 ) .
343In this mode, only the options which would be accepted by
344.Xr mount_mfs 8
345are valid.
346Furthermore, the following behavior, as done by
347.Xr mount_mfs 8 ,
348is duplicated:
349.Bl -bullet -offset indent
350.It
351The file mode of
352.Ar mount-point
353is set to
354.Li 01777
355as if
356.Fl p Ar 1777
357was given on the command line.
358.El
359.Sh SEE ALSO
360.Xr md 4 ,
361.Xr fstab 5 ,
362.Xr mdconfig 8 ,
363.Xr mount 8 ,
364.Xr newfs 8
365.Sh AUTHORS
366.An Dima Dorfman
367