A cell's initial database server machines are configured when DFS is installed and configured in the cell. If it becomes necessary to add or remove database server machines after initial cell configuration, perform the steps in Adding a Database Server Machine and Removing a Database Server Machine to properly configure information for Ubik. (You may be able to use the DCE installation and configuration program to modify the database servers configured in your cell. See your vendor's installation and configuration documentation for more information.)
When the Cache Manager on a DFS client machine needs information from the FLDB in a cell, the dfsbind process on the machine provides it with information about the names and network addresses of the Fileset Database machines for the cell. The information is valid for a limited amount of time, 24 hours by default, at which time the Cache Manager requests refreshed information from dfsbind; the Cache Manager also needs to refresh the information when it is restarted. The fxd process on a File Server machine passes the same information about Fileset Database machines for the local cell to the File Exporter on its machine, but only when it is restarted (generally when the machine is rebooted).
It is seldom necessary to restart client or server machines if you reconfigure a cell's Fileset Database machines. As long as at least one Fileset Database machine remains the same after reconfiguration, all machines can continue to access the FLDB via that machine. Eventually, all machines recognize the current set of Fileset Database machines as a result of routine machine administration and maintenance. It is never necessary to restart client or server machines if you reconfigure a cell's Backup Database machines.
Adding a Database Server Machine and Removing a Database Server Machine describe the steps required to add or remove a database server machine after initial cell configuration. Recall that each Fileset Database machine must run the FL Server (flserver process), and each Backup Database machine must run the Backup Server (bakserver process). These processes should be controlled by the Basic OverSeer (BOS) Server (bosserver process) on their machines, as recommended; if they are, you can use the appropriate bos commands to manipulate them.
Also recall that each FL Server must use the same admin.fl list, and that each Backup Server must use the same admin.bak list. In addition, the abbreviated DFS server principal of each Fileset Database machine must be included in the admin.fl list, and the abbreviated DFS server principal of each Backup Database machine must be included in the admin.bak list. A DFS server principal can be added directly to a list, or it can be present as a member of a group included in the list (for example, the group subsys/dce/dfs-fs-servers can be included in the admin.fl list).
Inclusion in the appropriate administrative list allows the database server process at the synchronization site to distribute changes to the database server processes at the secondary sites. The Update Server should be used to propagate these administrative lists from the System Control machine to their respective database server machines.
You can use the udebug command to obtain status information on Ubik database servers. The command is useful for diagnosing problems associated with Ubik. (See Part 2 of this guide and reference for complete information about the udebug command and its options. Refer to the sections at the beginning of this topic for more information about the processes that must run on either type of database server machine and the administrative lists used to specify who can control them; see Monitoring and Controlling Server Processes for more information about bos commands.)
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Adding a Database Server Machine
Removing a Database Server Machine