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AMD(8)			    System Manager's Manual			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 ] [	-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 auto-
       matically unmounted when	they appear to have become quiescent.

       Amd operates by attaching itself	as an NFS server to each of the	speci-
       fied directories.  Lookups within the specified directories are handled
       by  amd,	 which uses the	map defined by mapname to determine how	to re-
       solve 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 de-
       faults 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 nor-
	      malized 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	 over-
	      all 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 sepa-
	      rated 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 ev-
	      ery command line option amd has, and many	 more  that  are  only
	      available	 via  the configuration	file facility.	The configura-
	      tion 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 writ-
	      ten 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  per-
	      formance,	 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	trans-
       lation  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)

NAME | SYNOPSIS | DESCRIPTION | OPTIONS | FILES | CAVEATS | SEE ALSO | AUTHORS

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