DFS server and client machines can run the following processes: the BOS Server to monitor other processes; the Fileset Server, Fileset Location Server, and Replication Server to manipulate DFS filesets and their replicas; the Backup Server to contact the Backup Database; the butc process to back up file system data to tape; and the dfsd process to initialize the Cache Manager on a client machine.
Each DFS server or client machine must also run the RPC, CDS, and Security processes necessary for configuration as a DCE client machine. An RPC binding must be created in CDS for the DCE path name of each server machine, and a DFS server principal and associated account must also be created in the Registry Database for each server machine. The following sections assume that these requirements have been satisfied prior to configuring a machine as a DFS server or client machine. (See your vendor's installation and configuration documentation for more information about fulfilling these requirements.)
The system administrator determines, at installation, which processes are to be run on which machines. A machine's role is determined by the types of processes it runs. The information in the following topics details the different roles a machine can assume.
Each DFS server process has an associated administrative list. Users, groups, and server machines included on a process's administrative list can issue commands or calls that affect the process. Members can be added to administrative lists at any time. Using Administrative Lists and Keytab Files provides detailed information about the procedures used to create and maintain administrative lists. (See Part 2 of this guide and reference for complete information about the administrative privileges and permissions required to issue each DFS command.)
The Basic OverSeer (BOS) Server, or bosserver process, is not associated with any one machine role; it runs on every DFS server machine. Its primary function is to minimize system outages. It monitors other server processes on the local machine and restarts failed processes automatically.
By default, the BOS Server on each server machine stops and immediately restarts all DFS processes (including itself) on the machine once a week, at 4:00 a.m. on Sunday. It also checks for any newly installed binary files in the dcelocal/bin directory every morning at 5:00 a.m. (Note that these restart times can be configured.) If it finds any new files, which it does by checking for time stamps later than the time at which the corresponding process last started, it restarts the corresponding process. Because restarting processes causes a service outage, the default times are in the early morning hours, when an outage disturbs the fewest number of users. This brief suspension of services should have no effect on processes that are currently executing; the processes should continue normally once service resumes.
Install the BOS Server on all server machines to assist in administrative tasks on the machines. The admin.bos list is used to designate administrative users who can issue bos commands that affect the bosserver process on a server machine. Members of the admin.bos list can vary among different DFS administrative domains.
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