AMD(8)                                                     AMD(8)


NAME
       amd - automatically mount file systems

SYNOPSIS
       amd -H
       amd [ -F conf_file ]
       amd  [  -nprvHS  ] [ -a mount_point ] [ -c duration ] [ -d
       domain ] [ -k kernel-arch ] [ -l logfile ] [ -o op_sys_ver
       ] [ -t interval.interval ] [ -w interval ] [ -x log-option
       ] [ -y YP-domain ] [ -C cluster-name ] [ -D option ] [  -F
       conf_file ] [ -O op_sys_name ] [ -T tag ] [ directory map-
       name [ -map-options ] ] ...

DESCRIPTION
       Amd is a  daemon  that  automatically  mounts  filesystems
       whenever  a  file  or  directory within that filesystem is
       accessed.  Filesystems are  automatically  unmounted  when
       they appear to have become quiescent.

       Amd  operates by attaching itself as an NFS server to each
       of the specified directories.  Lookups within  the  speci-
       fied  directories  are  handled by amd, which uses the map
       defined by mapname to determine how to resolve the lookup.
       Generally,  this  will  be  a  host  name, some filesystem
       information and some mount options for the given  filesys-
       tem.

       In  the  first form depicted above, amd will print a short
       help string.  In the second form, if no options are speci-
       fied,  or  the  -F  is  used,  amd will read configuration
       parameters from  the  file  conf_file  which  defaults  to
       /etc/amd.conf.  The last form is described below.

OPTIONS
       -a temporary-directory
              Specify  an alternative location for the real mount
              points.  The default is /a.


       -c duration
              Specify a duration, in seconds, that  a  looked  up
              name  remains  cached when not in use.  The default
              is 5 minutes.


       -d domain
              Specify the local domain name.  If this  option  is
              not  given  the  domain name is determined from the
              hostname.


       -k kernel-arch
              Specifies the kernel architecture.   This  is  used
              solely to set the ${karch} selector.



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AMD(8)                                                     AMD(8)


       -l logfile
              Specify  a  logfile  in  which  to record mount and
              unmount events.  If logfile is  the  string  syslog
              then  the  log  messages will be sent to the system
              log daemon by syslog(3).  The default syslog facil-
              ity  used is LOG_DAEMON.  If you wish to change it,
              append its name to the log file name, delimited  by
              a  single  colon.   For  example, if logfile is the
              string syslog:local7 then Amd will log messages via
              syslog(3)  using  the  LOG_LOCAL7  facility  (if it
              exists on the system).


       -n     Normalize  hostnames.   The  name  refereed  to  by
              ${rhost}   is   normalized  relative  to  the  host
              database before  being  used.   The  effect  is  to
              translate aliases into ``official'' names.


       -o op_sys_ver
              Override  the  compiled-in  version  number  of the
              operating system.  Useful when the built in version
              is  not desired for backward compatibility reasons.
              For example, if the build in version is  ``2.5.1'',
              you  can  override  it  to ``5.5.1'', and use older
              maps that were written with the latter in mind.


       -p     Print PID.  Outputs the process-id of amd to  stan-
              dard output where it can be saved into a file.


       -r     Restart  existing  mounts.  Amd will scan the mount
              file table to determine which filesystems are  cur-
              rently  mounted.   Whenever one of these would have
              been auto-mounted, amd inherits it.


       -t timeout.retransmit
              Specify the NFS timeout interval, in  tenths  of  a
              second,  between  NFS/RPC  retries  (for UDP only).
              The default  is  0.8  seconds.   The  second  value
              alters  the  restransmit counter, which defaults to
              11 retransmissions.  Both of these values are  used
              by  the  kernel  to  communicate  with amd.  Useful
              defaults are supplied if either or both values  are
              missing.

              Amd  relies  on the kernel RPC retransmit mechanism
              to trigger mount  retries.   The  values  of  these
              parameters  change the overall retry interval.  Too
              long an interval gives poor  interactive  response;
              too short an interval causes excessive retries.




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AMD(8)                                                     AMD(8)


       -v     Version.  Displays version and configuration infor-
              mation on standard error.


       -w interval
              Specify an interval, in seconds,  between  attempts
              to  dismount  filesystems  that have exceeded their
              cached times.  The default is 2 minutes.


       -x options
              Specify run-time logging options.  The options  are
              a  comma  separated list chosen from: fatal, error,
              user, warn, info, map, stats, all.


       -y domain
              Specify an alternative NIS  domain  from  which  to
              fetch  the  NIS  maps.   The  default is the system
              domain name.  This option is ignored if NIS support
              is not available.


       -C cluster-name
              Specify an alternative HP-UX cluster name to use.


       -D option
              Select  from a variety of debug options.  Prefixing
              an option with the strings no reverses  the  effect
              of  that option.  Options are cumulative.  The most
              useful option is all.  Since -D is  only  used  for
              debugging  other  options  are not documented here:
              the current supported set of options is  listed  by
              the -v option and a fuller description is available
              in the program source.


       -F conf_file
              Specify an amd  configuration  file  to  use.   See
              amd.conf(5)  for description of this file's format.
              This configuration file  is  used  to  specify  any
              options  in lieu of typing many of them on the com-
              mand line.  The amd.conf file  includes  directives
              for  every  command  line  option amd has, and many
              more that are only available via the  configuration
              file facility.  The configuration file specified by
              this option is processed after  all  other  options
              had  been processed, regardless of the actual loca-
              tion of this option on the command line.


       -H     Print help and usage string.




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AMD(8)                                                     AMD(8)


       -O op_sys_name
              Override the compiled-in name of the operating sys-
              tem.   Useful when the built in name is not desired
              for backward compatibility reasons.   For  example,
              if  the  build in name is ``sunos5'', you can over-
              ride it to ``sos5'', and use older maps which  were
              written with the latter in mind.


       -S     Do  not  lock  the  running executable pages of amd
              into memory.  To improve amd's performance, systems
              that  support the plock(3) call, could lock the amd
              process into memory.  This way there is less chance
              the  operating  system will schedule, page out, and
              swap  the  amd  process  as  needed.   This   tends
              improves  amd's performance, at the cost of reserv-
              ing the memory used by the amd process  (making  it
              unavailable for other processes).  If this behavior
              is not desired, use the -S option.


       -T tag Specify a tag to use  with  amd.conf(5).   All  map
              entries  tagged  with  tag  will be processed.  Map
              entries that are not tagged are  always  processed.
              Map  entries  that are tagged with a tag other than
              tag will not be processed.


FILES
       /a   directory under  which  filesystems  are  dynamically
            mounted
       /etc/amd.conf
            default configuration file

CAVEATS
       Some care may be required when creating a mount map.

       Symbolic  links  on  an  NFS  filesystem can be incredibly
       inefficient.  In most implementations of NFS, their inter-
       polations  are  not  cached  by the kernel and each time a
       symlink is encountered during a  lookuppn  translation  it
       costs an RPC call to the NFS server.  It would appear that
       a large improvement  in  real-time  performance  could  be
       gained  by  adding  a cache somewhere.  Replacing symlinks
       with a suitable incarnation of the auto-mounter results in
       a  large real-time speedup, but also causes a large number
       of process context switches.

       A weird imagination is most useful to gain full  advantage
       of all the features.

SEE ALSO
       domainname(1),    hostname(1),   syslog(3),   amd.conf(5),
       amq(8), mount(8), umount(8)



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AMD(8)                                                     AMD(8)


       Amd - The 4.4 BSD Automounter

AUTHORS
       Jan-Simon Pendry <jsp@doc.ic.ac.uk>, Department of Comput-
       ing, Imperial College, London, UK.

       Erez  Zadok  <ezk@cs.columbia.edu>, Department of Computer
       Science, Columbia University, New York, USA.

       Other authors and contributors to am-utils are  listed  in
       the AUTHORS file distributed with am-utils.














































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