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 interval.interval
              Specify  the  interval,  in  tenths  of  a  second,
              between  NFS/RPC/UDP  retries.   The default is 0.8
              seconds.  The second values alters the  restransmit
              counter.  Useful defaults are supplied if either or
              both values are missing.


       -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.



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AMD(8)                                                     AMD(8)


       -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.


       -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.





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AMD(8)                                                     AMD(8)


       -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
       amd.conf(5),  amq(8),  domainname(1),  hostname(1),  auto-
       mount(8), mount(8), umount(8), mtab(5), syslog(3).

       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.



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AMD(8)                                                     AMD(8)


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























































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