=head1 NAME

vldb.DB0, vldb.DBSYS1 - Contain the Volume Location Database and associated log

=head1 DESCRIPTION

The file F<vldb.DB0> contains the Volume Location Database (VLDB), which
tracks the location of all AFS volumes stored on file server machines in
the cell. The Volume Location (VL) Server (B<vlserver> process) provides
information from the database to Cache Managers when they need to access
AFS data.

The file F<vldb.DBSYS1> is a log file in which the VL Server logs each
database operation before performing it. When an operation is interrupted,
the VL Server replays the log to complete the operation.

Both files are in binary format and reside in the F</usr/afs/db> directory
on each of the cell's database server machines. When the VL Server starts
or restarts on a given machine, it establishes a connection with its peers
and verifies that its copy of the database matches the copy on the other
database server machines. If not, the VL Servers call on AFS's distributed
database technology, Ubik, to distribute to all of the machines the copy
of the database with the highest version number.

Always use the commands in the B<vos> suite to administer the VLDB. It is
advisable to create an archive copy of the database on a regular basis,
using a tool such as the UNIX B<tar> command.

=head1 SEE ALSO

L<vldb_check(8)>,
L<vlserver(8)>,
L<vos(1)>

=head1 COPYRIGHT

IBM Corporation 2000. <http://www.ibm.com/> All Rights Reserved.

This documentation is covered by the IBM Public License Version 1.0.  It was
converted from HTML to POD by software written by Chas Williams and Russ
Allbery, based on work by Alf Wachsmann and Elizabeth Cassell.
