Provided by: am-utils_6.2+rc20110530-3ubuntu1_amd64 bug

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  ]  [  -A  arch  ]  [  -C cluster-name ] [ -D option ] [ -F conf_file ] [ -O
       op_sys_name ] [ -T tag ] [ directory mapname [ -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 specified 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 filesystem.

       In the first form depicted above, amd will print a short help string.  In the second form,
       if no options are specified, 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.

       -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 facility 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 standard 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  currently  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
              retransmit 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.

       -v     Version.  Displays version and configuration information 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, defaults,  and  all.   Note  that
              "fatal" and "error" are mandatory and cannot be turned off.

       -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.

       -A arch
              Specifies the OS architecture.  This is used solely to set the ${arch} selector.

       -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 command 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
              location 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 system.  Useful when  the  built  in
              name  is not desired for backward compatibility reasons.  For example, if the build
              in name is ``sunos5'', you can override 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 reserving 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 interpolations 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

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

       ``am-utils'' info(1) entry.

       Linux NFS and Automounter Administration by Erez Zadok, ISBN 0-7821-2739-8, (Sybex, 2001).

       http://www.am-utils.org

       Amd - The 4.4 BSD Automounter

AUTHORS

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

       Erez Zadok <ezk@cs.sunysb.edu>, Computer Science Department, Stony Brook University, Stony
       Brook, New York, USA.

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

                                         3 November 1989                                   AMD(8)