# Administration Reference

## vldb.DB0 and vldb.DBSYS1

Purpose

Contain the Volume Location Database and associated log

Description

The file 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 (vlserver process) provides information from the database to Cache Managers when they need to access AFS data.

The file 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 /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 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 tar command.

Related Information

vldb_check

vlserver

vos

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