1.5.1 Operating Environment

The following figure shows the configuration of the Fujitsu Enterprise Postgres operating environment. The tables given below list the roles of the OS resources and Fujitsu Enterprise Postgres resources.

Table 1.1 OS resources
Type	Role
Shared memory	Used when a database process exchanges information with an external process.
Semaphore

Table 1.2 Fujitsu Enterprise Postgres client resources
Type	Role
Connection service file	Specifies information, such as the host name, user name, and password, for connecting to Fujitsu Enterprise Postgres.
Password file	Securely manages the password for connecting to Fujitsu Enterprise Postgres.
CA certificate file	CA (certificate authority) certificate used for server authentication when encrypting communication data.

Table 1.3 Server resources of Fujitsu Enterprise Postgres
Type	Role
Database cluster	Database storage area on the database storage disk. It is a collection of databases managed by an instance.
System catalog	Contains information required for the system to run, including the database definition information and the operation information created by the user.
Default tablespace	Contains table files and index files stored by default.
Transaction log	Contains log information in case of a crash recovery or rollback. This is the same as the WAL (Write Ahead Log).
Work file	Work file used when executing applications or commands.
postgresql.conf	Contains information that defines the operating environment of Fujitsu Enterprise Postgres.
pg_hba.conf	Fujitsu Enterprise Postgres uses this file to authenticate individual client hosts.
Server certificate file	Contains information about the server certificate to be used when encrypting communication data and authenticating a server.
Server private key file	Contains information about the server private key to be used when encrypting communication data and authenticating a server
Tablespace	Stores table files and index files in a separate area from the database cluster. Specify a space other than that under the database cluster.
Backup	Stores the data required for recovering the database when an error, such as disk failure, occurs.
Database backup	Contains the backup data for the database.
Archive log	Contains the log information for recovery.
Mirrored transaction log (mirrored WAL)	Enables a database cluster to be restored to the state immediately before an error even if both the database cluster and transaction log fail when performing backup/recovery operations using the pgx_dmpall command or WebAdmin. Mirrored WALs can be used only for backup/recovery using the pgx_dmpall command or WebAdmin.
Core file	Fujitsu Enterprise Postgres process core file that is output when an error occurs during a Fujitsu Enterprise Postgres process.
Key management server or key management storage	Server or storage where the master encryption key file is located.
Master encryption key file	Contains the master encryption key to be used when encrypting storage data. The master encryption key file is managed on the key management server or key management storage.