You define which processes the BOS Server monitors by creating process entries in the dcelocal/var/dfs/BosConfig file on the local disk of each server machine. The information in a process entry defines how the process is to run. You control the process status (Run or NotRun) by changing the entry with bos commands. When the BOS Server starts, it creates a BosConfig file with no process entries if the file does not already exist.
The order in which process entries are added to or appear in the BosConfig file is irrelevant. The BOS Server restarts multiple processes virtually simultaneously. However, do not depend on one process starting before another simply because its entry precedes that of the other process in the BosConfig file. The BOS Server has no control over how long a process takes to start.
Caution: Do not directly edit the information in the BosConfig file; use only the commands described in this topic to alter the file. Directly editing the BosConfig file can result in changes to process entries of which the BOS Server is unaware. Such changes do not take effect until the BOS Server is restarted and again reads the file.
Each process entry includes the following information about its process:
· Its name. The name that appears in the BosConfig file for a process is the name used to refer to that process with any bos commands that require a process name.
· Its type. The type can be one of the following:
- simple - A simple process is a continuous process that runs independently of any other processes on a server machine. All standard DFS processes are simple processes. This process has a single parameter: the command to be executed.
- cron - A cron process, like a simple process, runs independently of other processes; however, a cron process runs periodically, not continuously. This process has two parameters: the first is the command that is to be executed; the second is the time that the command is to be executed.
· Its status flag. Status flags are for internal use only and do not appear in any output. The flag can have one of the following values:
- Run, meaning the process needs to run whenever possible. The BOS Server starts the process initially at reboot and restarts it automatically if it fails at any time. This flag is used to keep a process running at all times; for example, to ensure that the ftserver process on a File Server machine runs continuously. (The Run status flag appears in the BosConfig file as a 1.)
- NotRun, meaning the process never runs. The BOS Server never starts or automatically restarts the process; the process runs only when you instruct the BOS Server to start it. This flag is used to stop a process for an extended period of time; for example, to stop the upclient process from accessing new binary files while you test the current binaries. (The NotRun status flag appears in the BosConfig file as a 0.)
· Its command parameters. These parameters are used by the BOS Server to run the process.
The following output from the bos status command displays an entry from the BosConfig file. (See Listing Status and Machine Information for more information about the bos status command, which is used to list entries from the BosConfig file.)
Instance ftserver, (type is simple) currently running normally.
Process last started at Fri Nov 22 05:36:02 1991 (1 proc starts)
Parameter 1 is `dcelocal/bin/ftserver'
It is possible for the BOS Server's memory state to change independently of the BosConfig file. The BOS Server checks the BosConfig file whenever it starts or restarts, (in response to the bos restart command, at the general restart time, or at system reboot). At that time, the BOS Server transfers information from the file into memory and does not read the file again until it restarts.
Therefore, it is possible to use the bos shutdown command to stop a running process, even though its status flag in the BosConfig file is Run. Similarly, you can use the bos startup command to start a process running by setting its memory state status flag to Run without setting its status flag in the file to Run. The commands discussed in this topic can affect the BOS Server's memory state, the information in the BosConfig file, or both.
Starting or stopping certain processes, either temporarily or permanently, has an effect on the other processes that run on the other server machines in your cell. For example, an upserver process must run on each System Control machine and Binary Distribution machine. If you start or stop the process on one machine, you must start it on a replacement System Control or Binary Distribution machine. You must also modify the upclient processes on the appropriate server machines so that they reference the new System Control or Binary Distribution machine.