1.\" Copyright (c) 1989 Jan-Simon Pendry 2.\" Copyright (c) 1989 Imperial College of Science, Technology & Medicine 3.\" Copyright (c) 1989, 1991 The Regents of the University of California. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to Berkeley by 7.\" Jan-Simon Pendry at Imperial College, London. 8.\" 9.\" %sccs.include.redist.man% 10.\" 11.\" @(#)amd.8 5.3 (Berkeley) 03/17/91 12.\" 13.Dd March 17, 1991 14.Dt AMD 8 15.Os 16.Sh NAME 17.Nm amd 18.Nd automatically mount file systems 19.Sh SYNOPSIS 20.Nm amd 21.Op Fl nprv 22.Op Fl a Ar mount_point 23.Op Fl c Ar duration 24.Op Fl d Ar domain 25.Bk -words 26.Op Fl k Ar kernel-arch 27.Ek 28.Op Fl l Ar logfile 29.Op Fl t Ar interval.interval 30.Bk -words 31.Op Fl w Ar interval 32.Ek 33.Op Fl x Ar log-option 34.Op Fl y Ar YP-domain 35.Bk -words 36.Op Fl C Ar cluster-name 37.Ek 38.Op Fl D Ar option 39.Oo 40.Ar directory mapname 41.Op Fl map-options 42.Oc 43.Ar ... 44.Sh DESCRIPTION 45.Nm Amd 46is a daemon that automatically mounts filesystems 47whenever a file or directory 48within that filesystem is accessed. 49Filesystems are automatically unmounted when they 50appear to be quiescent. 51.Pp 52.Nm Amd 53operates by attaching itself as an 54.Tn NFS 55server to each of the specified 56.Ar directories . 57Lookups within the specified directories 58are handled by 59.Nm amd , 60which uses the map defined by 61.Ar mapname 62to determine how to resolve the lookup. 63Generally, this will be a host name, some filesystem information 64and some mount options for the given filesystem. 65.Sh OPTIONS 66.Bl -tag -width Ds 67.It Fl a Ar temporary-directory 68Specify an alternative location for the real mount points. 69The default is 70.Pa /a . 71.It Fl c Ar duration 72Specify a 73.Ar duration , 74in seconds, that a looked up name remains 75cached when not in use. The default is 5 minutes. 76.It Fl d Ar domain 77Specify the local domain name. If this option is not 78given the domain name is determined from the hostname. 79.It Fl k Ar kernel-arch 80Specifies the kernel architecture. This is used solely 81to set the ${karch} selector. 82.It Fl l Ar logfile 83Specify a logfile in which to record mount and unmount events. 84If 85.Ar logfile 86is the string 87.Em syslog , 88the log messages will be sent to the system log daemon by 89.Xr syslog 3 . 90.It Fl n 91Normalize hostnames. 92The name refered to by ${rhost} is normalized relative to the 93host database before being used. The effect is to translate 94aliases into ``official'' names. 95.It Fl p 96Print 97.Em PID . 98Outputs the process-id of 99.Nm amd 100to standard output where it can be saved into a file. 101.It Fl r 102Restart existing mounts. 103.Nm Amd 104will scan the mount file table to determine which filesystems 105are currently mounted. Whenever one of these would have 106been auto-mounted, 107.Nm amd 108.Em inherits 109it. 110.It Fl t Ar interval.interval 111Specify the 112.Ar interval , 113in tenths of a second, between 114.Tn NFS/RPC/UDP 115retries. 116The default is 0.8 seconds. 117The second values alters the restransmit counter. 118Useful defaults are supplied if either or both 119values are missing. 120.It Fl v 121Version. Displays version and configuration information on standard error. 122.It Fl w Ar interval 123Specify an 124.Ar interval , 125in seconds, between attempts to dismount 126filesystems that have exceeded their cached times. 127The default is 2 minutes. 128.It Fl y Ar domain 129Specify an alternative 130.Tn NIS 131domain from which to fetch the 132.Tn NIS 133maps. 134The default is the system domain name. 135This option is ignored if 136.Tn NIS 137support is not available. 138.It Fl x Ar options 139Specify run-time logging options. The options are a comma separated 140list chosen from: fatal, error, user, warn, info, map, stats, all. 141.It Fl D Ar option 142Select from a variety of debug options. Prefixing an 143option with the strings 144.Em no 145reverses the effect of that option. Options are cumulative. 146The most useful option is 147.Ar all . 148.El 149.Pp 150Since 151.Fl D 152is only used for debugging other options are not documented here: 153the current supported set of options is listed by the 154.Fl v 155option 156and a fuller description is available in the program source. 157.Sh FILES 158.Bl -tag -width /axx 159.It Pa /a 160directory under which filesystems are dynamically mounted 161.El 162.Sh CAVEATS 163Some care may be required when creating a mount map. 164.Pp 165Symbolic links on an 166.Tn NFS 167filesystem can be incredibly inefficient. 168In most implementations of NFS, their interpolations are not cached by 169the kernel and each time a symbolic link is 170encountered during a 171.Em lookuppn 172translation it costs an 173.Tn RPC 174call to the 175.Tn NFS 176server. 177A large improvement in real-time 178performance could be gained by adding a cache somewhere. 179Replacing 180.Xr symlinks 2 181with a suitable incarnation of the auto-mounter 182results in a large real-time speedup, but also causes a large 183number of process context switches. 184.Pp 185A weird imagination is most useful to gain full advantage of all 186the features. 187.Sh SEE ALSO 188.Xr amq 8 , 189.Xr domainname 1 , 190.Xr hostname 1 , 191.Xr automount 8 , 192.Xr mount 8 , 193.Xr umount 8 , 194.Xr mtab 5 , 195.Rs 196.%T Amd \- The 4.4 BSD Automounter 197.Re 198.Sh AUTHOR 199.An Jan-Simon Pendry 200<jsp@doc.ic.ac.uk>, Department of Computing, Imperial College, London, UK. 201.Sh HISTORY 202.Nm Amd 203.At 204