1AMD(8)                      System Manager's Manual                     AMD(8)
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NAME

6       amd - automatically mount file systems
7

SYNOPSIS

9       amd -H
10       amd [ -F conf_file ]
11       amd  [  -nprvHS ] [ -a mount_point ] [ -c duration ] [ -d domain ] [ -k
12       kernel-arch ] [ -l logfile ] [ -o op_sys_ver ] [ -t interval.interval ]
13       [  -w  interval  ]  [ -x log-option ] [ -y YP-domain ] [ -A arch ] [ -C
14       cluster-name ] [ -D option ] [ -F conf_file ] [ -O op_sys_name ]  [  -T
15       tag ] [ directory mapname [ -map-options ] ] ...
16

DESCRIPTION

18       Amd  is  a daemon that automatically mounts filesystems whenever a file
19       or directory within that filesystem is accessed.  Filesystems are auto‐
20       matically unmounted when they appear to have become quiescent.
21
22       Amd operates by attaching itself as an NFS server to each of the speci‐
23       fied directories.  Lookups within the specified directories are handled
24       by  amd,  which  uses  the  map  defined by mapname to determine how to
25       resolve the lookup.  Generally, this will be a host name, some filesys‐
26       tem information and some mount options for the given filesystem.
27
28       In  the  first form depicted above, amd will print a short help string.
29       In the second form, if no options are specified, or the -F is used, amd
30       will  read  configuration  parameters  from  the  file  conf_file which
31       defaults to /etc/amd.conf.  The last form is described below.
32

OPTIONS

34       -a temporary-directory
35              Specify an alternative location for the real mount points.   The
36              default is /a.
37
38
39       -c duration
40              Specify  a  duration,  in seconds, that a looked up name remains
41              cached when not in use.  The default is 5 minutes.
42
43
44       -d domain
45              Specify the local domain name.  If this option is not given  the
46              domain name is determined from the hostname.
47
48
49       -k kernel-arch
50              Specifies  the  kernel architecture.  This is used solely to set
51              the ${karch} selector.
52
53
54       -l logfile
55              Specify a logfile in which to record mount and  unmount  events.
56              If  logfile  is  the string syslog then the log messages will be
57              sent to the system log daemon by syslog(3).  The default  syslog
58              facility  used  is LOG_DAEMON.  If you wish to change it, append
59              its name to the log file name, delimited by a single colon.  For
60              example,  if  logfile  is the string syslog:local7 then Amd will
61              log messages via syslog(3) using the LOG_LOCAL7 facility (if  it
62              exists on the system).
63
64
65       -n     Normalize  hostnames.   The name refereed to by ${rhost} is nor‐
66              malized relative to the host database before  being  used.   The
67              effect is to translate aliases into ``official'' names.
68
69
70       -o op_sys_ver
71              Override the compiled-in version number of the operating system.
72              Useful when the built in version is  not  desired  for  backward
73              compatibility  reasons.  For example, if the build in version is
74              ``2.5.1'', you can override it to ``5.5.1'', and use older  maps
75              that were written with the latter in mind.
76
77
78       -p     Print  PID.   Outputs  the  process-id of amd to standard output
79              where it can be saved into a file.
80
81
82       -r     Restart existing mounts.  Amd will scan the mount file table  to
83              determine which filesystems are currently mounted.  Whenever one
84              of these would have been auto-mounted, amd inherits it.
85
86
87       -t timeout.retransmit
88              Specify the NFS timeout interval, in tenths of a second, between
89              NFS/RPC  retries  (for  UDP  only).  The default is 0.8 seconds.
90              The second value alters the retransmit counter,  which  defaults
91              to  11  retransmissions.   Both  of these values are used by the
92              kernel to communicate with amd.  Useful defaults are supplied if
93              either or both values are missing.
94
95              Amd  relies  on  the  kernel RPC retransmit mechanism to trigger
96              mount retries.  The values of these parameters change the  over‐
97              all retry interval.  Too long an interval gives poor interactive
98              response; too short an interval causes excessive retries.
99
100
101       -v     Version.  Displays  version  and  configuration  information  on
102              standard error.
103
104
105       -w interval
106              Specify  an  interval,  in seconds, between attempts to dismount
107              filesystems that have exceeded their cached times.  The  default
108              is 2 minutes.
109
110
111       -x options
112              Specify run-time logging options.  The options are a comma sepa‐
113              rated list chosen from: fatal, error,  user,  warn,  info,  map,
114              stats,  defaults,  and  all.   Note that "fatal" and "error" are
115              mandatory and cannot be turned off.
116
117
118       -y domain
119              Specify an alternative NIS domain from which to  fetch  the  NIS
120              maps.   The  default  is the system domain name.  This option is
121              ignored if NIS support is not available.
122
123
124       -A arch
125              Specifies the OS architecture.  This is used solely to  set  the
126              ${arch} selector.
127
128
129       -C cluster-name
130              Specify an alternative HP-UX cluster name to use.
131
132
133       -D option
134              Select  from  a  variety  of debug options.  Prefixing an option
135              with the strings no reverses the effect of that option.  Options
136              are  cumulative.   The  most  useful option is all.  Since -D is
137              only used for debugging other options are not  documented  here:
138              the  current supported set of options is listed by the -v option
139              and a fuller description is available in the program source.
140
141
142       -F conf_file
143              Specify an amd configuration file to use.  See  amd.conf(5)  for
144              description  of  this file's format.  This configuration file is
145              used to specify any options in lieu of typing many  of  them  on
146              the  command  line.   The  amd.conf file includes directives for
147              every command line option amd has, and many more that  are  only
148              available  via  the configuration file facility.  The configura‐
149              tion file specified by this option is processed after all  other
150              options had been processed, regardless of the actual location of
151              this option on the command line.
152
153
154       -H     Print help and usage string.
155
156
157       -O op_sys_name
158              Override the compiled-in name of the operating  system.   Useful
159              when the built in name is not desired for backward compatibility
160              reasons.  For example, if the build in name is  ``sunos5'',  you
161              can override it to ``sos5'', and use older maps which were writ‐
162              ten with the latter in mind.
163
164
165       -S     Do not lock the running executable pages of amd into memory.  To
166              improve  amd's  performance,  systems  that support the plock(3)
167              call, could lock the amd process into memory.  This way there is
168              less  chance  the  operating system will schedule, page out, and
169              swap the amd process as needed.  This tends improves amd's  per‐
170              formance,  at  the  cost of reserving the memory used by the amd
171              process (making it unavailable for other  processes).   If  this
172              behavior is not desired, use the -S option.
173
174
175       -T tag Specify  a  tag to use with amd.conf(5).  All map entries tagged
176              with tag will be processed.  Map entries that are not tagged are
177              always  processed.  Map entries that are tagged with a tag other
178              than tag will not be processed.
179
180

FILES

182       /a   directory under which filesystems are dynamically mounted
183
184       /etc/amd.conf
185            default configuration file
186

CAVEATS

188       Some care may be required when creating a mount map.
189
190       Symbolic links on an NFS filesystem can be incredibly inefficient.   In
191       most implementations of NFS, their interpolations are not cached by the
192       kernel and each time a symlink is encountered during a lookuppn  trans‐
193       lation  it costs an RPC call to the NFS server.  It would appear that a
194       large improvement in real-time performance could be gained by adding  a
195       cache somewhere.  Replacing symlinks with a suitable incarnation of the
196       auto-mounter results in a large real-time speedup, but  also  causes  a
197       large number of process context switches.
198
199       A  weird  imagination  is most useful to gain full advantage of all the
200       features.
201

SEE ALSO

203       amq(8), domainname(1), hostname(1), syslog(3).   amd.conf(5),  mtab(5),
204       automount(8), mount(8), umount(8),
205
206       ``am-utils'' info(1) entry.
207
208       Linux   NFS   and   Automounter  Administration  by  Erez  Zadok,  ISBN
209       0-7821-2739-8, (Sybex, 2001).
210
211       http://www.am-utils.org
212
213       Amd - The 4.4 BSD Automounter
214

AUTHORS

216       Jan-Simon Pendry <jsp@doc.ic.ac.uk>, Department of Computing,  Imperial
217       College, London, UK.
218
219       Erez  Zadok  <ezk@cs.sunysb.edu>,  Computer  Science  Department, Stony
220       Brook University, Stony Brook, New York, USA.
221
222       Other authors and contributors to am-utils are listed  in  the  AUTHORS
223       file distributed with am-utils.
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227                                3 November 1989                         AMD(8)
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