Prepare Disk Storage Locations

This section is included in the Vertica Installation Guide and Database Administrator's Guide because the choice of disk storage locations for a database can be made at installation time or at database configuration time.

Prepare the disk locations that will contain the Vertica

catalog and data files (

physical schema) on drives local to each host in the

cluster. You can use a single directory to contain both the catalog and data files or you can use separate directories. If using separate directories, they can be on different drives.

A cluster generally refers a collection of hosts or a collection of nodes bound to a database. A cluster is not part of a database definition and thus does not have a name.

A physical schema consists of a set of projections used to store data on disk. The projections in the physical schema are based on the objects in the Logical Schema.

In Vertica, the catalog is a set of files that contain information (metadata) about the objects in a database (nodes, tables, constraints, projections, etc.) The catalog is replicated on all nodes in a cluster.

The catalog and data directory pathnames must be identical on each host in the cluster and the directories must be owned by the

Database Administrator.

The database administrator (DBA) is the Linux user account that owns the database catalog and data storage on disk. The DBA can bypass all database authorization rules. However, the DBA must supply a password to connect to a running database and to use Administration Tools commands that affect a running database. The DBA can drop a stopped database without supplying a password.

If you place catalog and data files on a shared drive for testing purpose, each host must have its own catalog and data locations. In other words, hosts cannot share catalog or data locations.

When you install Vertica, the install_vertica script's data_directory parameter allows you to specify a directory to contain database data and catalog files. The default is the Database Administrator's default home directory:

There is no requirement that you actually use this directory. It is created for your convenience. However, if you choose a different location, make sure that the location exists on each host in the cluster and is owned by the Database Administrator before creating a database.

Make sure that whatever disk storage location you specify at installation time does not already exist on any cluster host.

For example, if you created a database for evaluation purposes, dropped the database, and want to reuse the database name, make sure that the disk storage location used for the first database has been deleted. The next section describes the subdirectories created when you create a database.

When you invoke the Create Database command in the Administration Tools, the following dialog allows you to specify the actual catalog and data locations. These locations much exist on each host in the cluster and must be owned by the Database Administrator.

For example, if you use the default value (the Database Administrator's home directory) of /home/dbadmin for the Stock_Schema example database, the catalog and data directories would be:

Catalog and data pathnames must contain only alphanumeric characters and cannot have leading space characters. Failure to comply with these restrictions may result in database creation failure.