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BosConfig - Defines server processes for the BOS Server to monitor
The BosConfig file lists the processes that the Basic OverSeer (BOS)
Server monitors on its server machine, and thus defines which AFS
server processes run on the machine. It specifies how the BOS Server
reacts when a process fails, and also defines the times at which the
BOS Server automatically restarts processes as part of performance
maintenance. The file must reside in the /var/lib/openafs/local
directory on each AFS server machine.
A server process entry in the BosConfig file records the following
· The entry type, which is one of the following:
Designates a server process that runs periodically instead of
continuously. The BOS Server starts a cron process only at
specified times, not whenever it fails. All standard AFS
process entries except "fs" are simple (there are no standard
fs Designates a group of interdependent server processes. If one
of the processes fails, the BOS Server must coordinate its
restart with the restart of the other processes in the group,
possibly by stopping them first.
There is only one standard entry of this type, for which the
conventional name is "fs". It combines three server processes:
the File Server (fileserver process), the Volume Server
(volserver process), and the Salvager (salvager process). These
processes all operate on the same data--the AFS data stored on
an AFS server machine’s /vicep partitions and mounted in the
AFS filespace--but in different ways. Grouping the processes
prevents them from attempting to access the same data
simultaneously, which can cause corruption.
During normal operation, the Salvager process is not active. If
the File Server process fails, however, the BOS Server stops
the Volume Server process and runs the Salvager process to
correct any corruption that resulted from the failure. (The
administrator can also issue the bos salvage command to invoke
the Salvager process.) If the Volume Server fails, the BOS
Server can restart it without stopping the File Server or
running the Salvager.
Designates a server process that runs independently of any
other on the server machine. If a simple process fails, the BOS
Server does not have to coordinate its restart with any other
· The entry name. The conventional name for an entry in the BosConfig
file and the associated process matches the binary filename. When
issuing any bos command that takes the -instance argument, identify
each process by the name used in the BosConfig file. For a list of
the names, see the bos create reference page.
· The process’s status flag, which determines whether the BOS Server
attempts to start the process in two cases: each time the BOS
Server itself restarts, and when the process fails. The BosConfig
file currently uses a binary notation to indicate whether the BOS
Server attempts to restart the process as necessary or does not
monitor it at all. For the sake of clarity, the AFS documentation
refers to the flags as "Run" and "NotRun" instead. Only a system
administrator, not the BOS Server, can change the flag.
· One or more command parameters which the BOS Server invokes to
start the process or processes associated with the entry:
· A "cron" entry has two command parameters, the first the
complete pathname to the program, and the second the time at
which the BOS Server invokes the program.
· The "fs" entry has three command parameters, each the complete
pathname to the fileserver, volserver, and salvager programs,
in that order.
· A "simple" entry has only one command parameter, the complete
pathname to the program.
In addition to server process entries, the BosConfig file specifies the
times at which the BOS Server performs two types of automatic process
· The general restart time at which the BOS Server restarts itself
and then each process for which the entry in the BosConfig file has
status flag "Run". The default setting is Sunday at 4:00 a.m.
· The binary restart time at which the BOS Server restarts any server
process for which the time stamp on the binary file in the
/usr/lib/openafs directory is later than the last restart time for
the process. The default is 5:00 a.m.
Although the BosConfig file is in ASCII format, do not use a text
editor to alter it. Its format is subject to change and incorrectly
formatted entries can prevent server startup in ways that are difficult
to diagnose. Instead always use the appropriate commands from the bos
· The bos create command to create an entry in the file and start the
· The bos delete command to remove an entry from the file after the
bos stop command is used to stop the associated process.
· The bos getrestart command to display the times at which the BOS
Server performs automatic restarts.
· The bos setrestart command to set the times at which the BOS Server
performs automatic process restarts.
· The bos start command to change an entry’s status flag to "Run" and
start the associated process.
· The bos status command to display all processes listed in the file.
· The bos stop command to change an entry’s status flag to "NotRun"
and stop the associated process.
There are also bos commands that start and stop processes without
changing entries in the BosConfig file. The BOS Server reads the
BosConfig file only when it starts, transferring the information into
its memory. Thus a process’s status as represented in the BOS Server’s
memory can diverge from its status in the BosConfig file. The following
commands change a process’s status in the BOS Server’s memory only:
· The bos restart command restarts a specified set of processes, all
processes, or all processes other than the BOS Server.
· The bos shutdown command stops a process.
· The bos startup command starts a process.
bos_create(8), bos_delete(8), bos_getrestart(8), bos_restart(8),
bos_setrestart(8), bos_shutdown(8), bos_start(8), bos_startup(8),
bos_status(8), bos_stop(8), bos_salvage(8), fileserver(8), salvager(8),
IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.
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and Russ Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.