The following example shows a typical PostgreSQL resource hierarchy:

The dependencies in the above example correspond to the following protected resources:

Resource
PostgreSQL Software Component
LKIP.EXAMPLE.COM Protects the switchable IP address used for client connections
var/lib/pgsql/data Protects the database data directory (PGDATA)
var/lib/pgsql/exec Protects the PostgreSQL server and client executables (when executables are installed on a shared file system)
var/lib/pgsql/log Protects the database log file directory (when the log path is located on a shared file system)
var/lib/pgsql/pg_xlog Protects the database transaction log directory (PGDATA/pg_xlog) The transaction log directory is also referred to as Write-Ahead-Log directory.
var/lib/pgsql/socket_path Protects the database socket directory (when the socket path is located on a shared file system).

In the event of failover, LifeKeeper will bring the file system, IP address and database resources (including all the resource dependencies) in service on a backup server. Clients will be disconnected and will need to re-connect to the server. Any SQL statement that has not been committed will need to be re-entered.

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