MASTER(8) MASTER(8)
NAME
master - Postfix master process
SYNOPSIS
master [-c config_dir] [-D] [-t] [-v]
DESCRIPTION
The master daemon is the resident process that runs Post-
fix daemons on demand: daemons to send or receive messages
via the network, daemons to deliver mail locally, etc.
These daemons are created on demand up to a configurable
maximum number per service.
Postfix daemons terminate voluntarily, either after being
idle for a configurable amount of time, or after having
serviced a configurable number of requests. The exception
to this rule is the resident Postfix queue manager.
The behavior of the master daemon is controlled by the
master.cf configuration file. The table specifies zero or
more servers in the UNIX or INET domain, or servers that
take requests from a FIFO. Precise configuration details
are given in the master.cf file, and in the manual pages
of the respective daemons.
Options:
-c config_dir
Read the main.cf and master.cf configuration files
in the named directory.
-D After initialization, run a debugger on the master
process. The debugging command is specified with
the debugger_command in the main.cf global configu-
ration file.
-t Test mode. Return a zero exit status when the mas-
ter.pid lock file does not exist or when that file
is not locked. This is evidence that the master
daemon is not running.
-v Enable verbose logging for debugging purposes. This
option is passed on to child processes. Multiple -v
options make the software increasingly verbose.
Signals:
SIGHUP Upon receipt of a HUP signal (e.g., after postfix
reload), the master process re-reads its configura-
tion files. If a service has been removed from the
master.cf file, its running processes are termi-
nated immediately. Otherwise, running processes
are allowed to terminate as soon as is convenient,
so that changes in configuration settings affect
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MASTER(8) MASTER(8)
only new service requests.
SIGTERM
Upon receipt of a TERM signal (e.g., after postfix
abort), the master process passes the signal on to
its child processes and terminates. This is useful
for an emergency shutdown. Normally one would ter-
minate only the master (postfix stop) and allow
running processes to finish what they are doing.
DIAGNOSTICS
Problems are reported to syslogd(8).
BUGS
ENVIRONMENT
MAIL_DEBUG
After initialization, start a debugger as specified
with the debugger_command configuration parameter
in the main.cf configuration file.
MAIL_CONFIG
Directory with Postfix configuration files.
CONFIGURATION PARAMETERS
The following main.cf parameters are especially relevant
to this program. See the Postfix main.cf file for syntax
details and for default values. Use the postfix reload
command after a configuration change.
Miscellaneous
mail_owner
The owner of the mail queue and of most Postfix
processes.
command_directory
Directory with Postfix support programs.
daemon_directory
Directory with Postfix daemon programs.
queue_directory
Top-level directory of the Postfix queue. This is
also the root directory of Postfix daemons that run
chrooted.
Resource controls
default_process_limit
Default limit for the number of simultaneous child
processes that provide a given service.
max_idle
Limit the time in seconds that a child process
waits between service requests.
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MASTER(8) MASTER(8)
max_use
Limit the number of service requests handled by a
child process.
service_throttle_time
Time to avoid forking a server that appears to be
broken.
FILES
/etc/postfix/main.cf: global configuration file.
/etc/postfix/master.cf: master process configuration file.
/var/spool/postfix/pid/master.pid: master lock file.
SEE ALSO
qmgr(8) queue manager
pickup(8) local mail pickup
syslogd(8) system logging
LICENSE
The Secure Mailer license must be distributed with this
software.
AUTHOR(S)
Wietse Venema
IBM T.J. Watson Research
P.O. Box 704
Yorktown Heights, NY 10598, USA
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