amd - automatically mount file systems
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 ] ] ...
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.
  - -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.
    
  
  - /a
- directory under which filesystems are dynamically mounted
- /etc/amd.conf
- default configuration file
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.
domainname(1), hostname(1), syslog(3). amd.conf(5),
  mtab(5), amq(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
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.