Coda File System

3.2. Processes

Each of the dedicated file servers must run a number of processes. These processes are shown in Table 3-1 and are described below.

Table 3-1. Server processes

File Server Process The codasrv process interacts with the venus process on clients. Together they fulfill user requests for shared data stored on the server. When started, the server process will salvage the file system. The presence of a file called SHUTDOWN in the /vice/srv directory indicates that the server process exited normally.
Auth Server Process The auth2 process runs on all servers. It validates user passwords and issues a token for that user if the password is correct. However, passwords may only be changed at the SCM. Hence, the password database is read-only replicated to all servers and the SCM maintains the read-write replica. Changes to the password file are updated automatically through the updateclnt/updatesrv processes described below. On all servers (except the SCM), auth2 is invoked with the -chk option.
Update Client Process The updateclnt process works in conjunction with the updatesrv process (running on the SCM) to keep read-only copies of system files and databases in sync with their corresponding read-write copy. The updateclnt process checks with the updatesrv process on the SCM periodically to ensure that the read-only copy on this server is the latest copy. Thus, when the read-write copy is updated, the read-only copies will be automatically updated after some delay.

Figure 3-2 lists the typical processes of a running file server.

Figure 3-2. Typical processes on file-server

    0 ??  DLs    0:35.41 (swapper)
    1 ??  Is     0:00.26 /sbin/init 
    2 ??  DL     0:39.89 (pagedaemon)
  115 ??  Ss     4:27.31 syslogd 
  198 ??  Is    55:36.88 update 30 
  200 ??  Ss     2:06.16 cron 
 7297 ??  Ss     0:00.61 /usr/pkg/sbin/rpc2portmap 
 7301 ??  Ss     0:12.36 /usr/pkg/sbin/updatesrv -p /vice/db 
 7601 ??  Is     0:04.51 auth2 
 9624 ??  Ss     0:05.78 updateclnt -h falla -q coda_udpsrv 
 9907 ??  S
s    0:11.37 codasrv -t 1000 -trunc 5 -rvm /dev/rwd1a /dev/rwd0g 94
 9899 p0  IW     0:00.02 /bin/sh /usr/pkg/sbin/startserver