1 fs mkmount AFS Commands fs mkmount
6 fs mkmount -- create a mount point for a volume.
9 fs mkmount -dir <directory> -vol <volume name> [-cell <cell
10 name>] [-rw] [-fast] [-root] [-help]
12 ACCEPTABLE ABBREVIATIONS/ALIASES
14 fs mk -d <directory> -v <volume name> [-c <cell name>]
19 Creates a mount point called directory for the volume volume
20 name. The volume's root directory is also named directory.
21 Mount points look and act just like standard UNIX directory
22 structures, because when the Cache Manager encounters a
23 mount point directory in a pathname, it knows to look in the
24 indicated volume for the elements listed under directory.
26 It is possible, although not recommended, to create more
27 than one mount point to a volume.
31 There are several types of mount points, because mount
32 points can vary along three dimensions. The following will
33 discuss the three dimensions in turn, explaining how they
34 affect the Cache Manager's interpretation of the mount
37 Dimension 1: Volume Type
39 The first dimension concerns which type of volume
40 (ReadWrite, ReadOnly or Backup) is named in the mount point.
41 ReadOnly and Backup volumes are distinguished by a .readonly
42 or .backup extension, respectively. When a mount point
43 names a volume with either extension, the Cache Manager
44 accesses the specified volume only, ignoring Dimension 2
45 (the mount point's type). In other words, the Cache Manager
46 will never access the ReadWrite version of a volume if the
47 mount point explicitly names the ReadOnly or Backup version.
48 If the named ReadOnly or Backup volume is inaccessible, the
49 Cache Manager reports an error.
51 If the volume name does not include a .backup or .readonly
52 extension, then the volume is ReadWrite. The Cache Manager
53 considers Dimension 2.
55 Dimension 2: Mount Point Type
57 Note: This dimension is relevant only if the volume
58 indicated in the mount point is ReadWrite. Only Dimension 1
59 is relevant if the named volume is ReadOnly or Backup.
61 The second dimension concerns whether the mount point itself
62 is "regular" or "ReadWrite":
64 - When the Cache Manager encounters a regular mount
68 point (one naming a ReadWrite volume), it tries to
69 access a copy of the volume that is of same type
70 (ReadWrite or ReadOnly) as the volume which houses
71 the mount point. If there is no volume of the
72 same type, it will access the type that is
75 Almost all mount points are of this type. Its
76 advantage is that the Cache Manager is free to
77 access the most readily available form of the
78 volume. When the Cache Manager starts in a
79 ReadOnly volume, this type of mount point means
80 that it traverses a "ReadOnly path," which can be
81 efficient because no callbacks are necessary.
83 The issuer creates a regular mount point by
84 providing only the required -dir and -vol
87 - When the Cache Manager encounters a ReadWrite
88 mount point, it accesses only the ReadWrite
89 version of the indicated volume. (This assumes
90 that the volume does not have a .backup or
91 .readonly extension. Mounting a Backup or
92 ReadOnly volume with a ReadWrite mount point is
93 possible but unnecessary, as the Cache Manager
94 handles those volume types in the same way whether
95 their mount point is regular or ReadWrite. See
98 A ReadWrite mount point is generally used to mount
99 only one volume in a cell: its root.cell volume at
100 the second level in the file tree, just below
101 /afs. Conventionally, root.cell is also mounted
102 with a regular mount point at the same level. The
103 two mount points are distinguished by the
104 placement of a period at the start of the
105 ReadWrite mount point's name (see the EXAMPLES
106 section). The existence of a ReadWrite mount
107 point for root.cell allows the system
108 administrator to switch onto a "ReadWrite" path
109 and thus be sure he or she is accessing the
110 ReadWrite version of a volume when that is
113 The issuer creates a ReadWrite mount point by
116 Dimension 3: Cellular versus Local
118 The third dimension concerns which cell the volume resides
119 in. A cellular mount point indicates to the Cache Manager
120 that the volume resides in a foreign cell (and specifies
121 which one). If the mount point is not cellular, then the
122 Cache Manager assumes that the volume resides in the same
123 cell as the mount point does.
125 Normally, cellular mount points are used only at the second
126 level in a cell's file tree (i.e., at the "cell" level just
127 below /afs), to mount the root.cell volumes for foreign
128 cells that are to be visible in the local cell. It is
132 possible to create cellular mount points (mount foreign
133 volumes) at other levels in the tree. Doing so is not
134 recommended, however, as it can make it difficult to
135 determine which cell a given pathname leads to.
137 Cellular mount points can be either regular or ReadWrite:
139 - A regular cellular mount point not only tells the
140 Cache Manager to cross into a foreign cell, but
141 also to access the ReadOnly version of the
142 indicated volume if possible. The advantage is
143 that the Cache Manager traverses a "ReadOnly path"
144 in the foreign cell, even if the mount point for
145 the indicated volume resides in a ReadWrite
146 volume. This is particularly useful when crossing
147 into foreign cells that are too small to replicate
148 their root.afs volume.
150 To create a regular cellular mount point, the
151 issuer uses the -cell argument to specify the cell
152 name, and adds the -root flag.
154 - A ReadWrite cellular mount point tells the Cache
155 Manager to cross into a foreign cell and access
156 the ReadWrite version of the volume (assuming that
157 the volume does not have a .backup or .readonly
158 extension). Use of this type of mount point is
159 discouraged, because accessing ReadWrite volumes
160 means the File Server has to issue callbacks, an
161 extra load it is not fair to impose from outside
162 the cell. In general, only a cell's own
163 administrators need to access the ReadWrite
166 To create a ReadWrite cellular mount point, the
167 issuer uses the -cell argument to specify the cell
168 name, and adds both the -root and -rw flags.
169 Because this is not recommended, no example of it
172 Mounting foreign volumes in foreign cells
174 In addition to mounting volumes in the local cell, the
175 fs mkmount allows a user who possesses the necessary access
176 rights in a foreign cell to create a regular, non-cellular
177 mount point in a foreign cell's file tree while working on a
178 machine in his or her local cell. In other words, the
179 issuer can mount a volume from a foreign cell in that cell's
180 file space as though he or she were working at a machine in
183 To mount a foreign volume in foreign cell, specify the cell
184 name with -cell, but do not use the -root flag.
188 Distinguishing the types of mount points
190 The output of fs lsmount uses various symbols to distinguish
191 the different types of mount points. See the Output section
192 of that command's description.
196 -dir names the directory to be created as a mount point to
197 the named volume. It should not already exist. If
198 the issuer does not specify a pathname, the mount
199 point is created as a subdirectory of the current
202 -vol names the volume to be mounted. Add the .readonly or
203 .backup extension if appropriate. The volumeID is
206 Note: When creating a cellular mount point, do not
207 specify the cell name as part of this argument, as was
208 necessary in previous versions of AFS that did not
209 have the -root flag. Instead, include the -root flag
210 and use the -cell argument to specify the cell name;
211 the command interpreter will automatically prepend the
212 cell name to the volume name, separating them with a
215 -cell names the cell in which the volume resides. When
216 creating a cellular mount point, combine this argument
217 with the -root flag. When mounting a foreign volume
218 in a foreign cell, use this argument alone.
220 -rw designates the mount point as ReadWrite, which forces
221 the Cache Manager to access only the ReadWrite copy of
222 a volume that does not have a .backup or .readonly
223 extension. Without this flag, the mount point is
226 -fast indicates that the VL Server should not check that
227 there is a VLDB entry for the volume to be mounted.
228 By default, the VL Server does check and prints a
229 warning message if there is no VLDB entry; the mount
230 point is created in any case.
232 -root creates a cellular mount point.
234 -help prints the online help entry for this command. Do not
235 provide any other arguments or flags with this one.
236 See section 3.1 in the Reference Manual for more
241 Note: These examples illustrate only the recommended
242 combinations and use of arguments. The OUTPUT section of
243 fs lsmount's description shows what each mount point looks
246 The following creates a regular mount point. It mounts
247 user.smith at /afs/transarc.com/usr/smith.
251 % cd /afs/transarc.com/usr % fs mk smith user.smith
255 The following creates both a ReadWrite and regular mount
256 point for the Transarc Corporation cell's root.cell volume,
257 in that cell's file tree. It follows the convention of
258 putting a period at the beginning of the ReadWrite mount
261 % fs mk /afs/transarc.com root.cell % fs mk
262 /afs/.transarc.com root.cell -rw
264 The following mounts the root.cell volume belonging to
265 Carnegie Mellon University's Andrew cell in the Transarc
266 Corporation cell's file tree, creating a regular, cellular
267 mount point called andrew.cmu.edu. When a Transarc
268 Corporation Cache Manager encounters this mount point, it
269 will cross into the Andrew cell on a ReadOnly path.
271 % fs mk /afs/andrew.cmu.edu root.cell -c andrew.cmu.edu
274 The following illustrates the creation of a mount point in a
275 foreign cell, using Transarc Corporation's regular cell
276 (transarc.com) as the local cell and its test cell
277 (test.transarc.com) as the foreign cell. Suppose that while
278 working on a machine belonging to the transarc.com cell, a
279 Transarc Corporation user wants to mount a test.transarc.com
280 volume called user.test5 at
281 /afs/test.transarc.com/usr/test5. She has the INSERT and
282 ADMINISTER rights for /afs/test.transarc.com/usr. Note that
283 the effect is just the same as if the issuer were working on
284 a machine belonging to the test.transarc.com cell and
285 omitted the -c test.transarc.com part of the command.
287 % cd /afs/test.transarc.com/usr % fs mk test5 user.test5 -c
292 Issuer must have INSERT and ADMINISTER access for the
293 directory that is to contain the mount point.
297 fs lsmount fs rmmount