initdb - create a new PostgreSQL database cluster

initdb creates a new PostgreSQL database cluster.

       Creating a database cluster consists of creating the directories in which the cluster data will live,
       generating the shared catalog tables (tables that belong to the whole cluster rather than to any
       particular database), and creating the postgres, template1, and template0 databases. The postgres
       database is a default database meant for use by users, utilities and third party applications.  template1
       and template0 are meant as source databases to be copied by later CREATEDATABASE commands.  template0
       should never be modified, but you can add objects to template1, which by default will be copied into
       databases created later. See Section 22.3 for more details.

       Although initdb will attempt to create the specified data directory, it might not have permission if the
       parent directory of the desired data directory is root-owned. To initialize in such a setup, create an
       empty data directory as root, then use chown to assign ownership of that directory to the database user
       account, then su to become the database user to run initdb.

       initdb must be run as the user that will own the server process, because the server needs to have access
       to the files and directories that initdb creates. Since the server cannot be run as root, you must not
       run initdb as root either. (It will in fact refuse to do so.)

       For security reasons the new cluster created by initdb will only be accessible by the cluster owner by
       default. The --allow-group-access option allows any user in the same group as the cluster owner to read
       files in the cluster. This is useful for performing backups as a non-privileged user.

       initdb initializes the database cluster's default locale and character set encoding. These can also be
       set separately for each database when it is created.  initdb determines those settings for the template
       databases, which will serve as the default for all other databases.

       By default, initdb uses the locale provider libc (see Section 23.1.4). The libc locale provider takes the
       locale settings from the environment, and determines the encoding from the locale settings.

       To choose a different locale for the cluster, use the option --locale. There are also individual options
       --lc-* and --icu-locale (see below) to set values for the individual locale categories. Note that
       inconsistent settings for different locale categories can give nonsensical results, so this should be
       used with care.

       Alternatively, initdb can use the ICU library to provide locale services by specifying
       --locale-provider=icu. The server must be built with ICU support. To choose the specific ICU locale ID to
       apply, use the option --icu-locale. Note that for implementation reasons and to support legacy code,
       initdb will still select and initialize libc locale settings when the ICU locale provider is used.

       When initdb runs, it will print out the locale settings it has chosen. If you have complex requirements
       or specified multiple options, it is advisable to check that the result matches what was intended.

       More details about locale settings can be found in Section 23.1.

       To alter the default encoding, use the --encoding. More details can be found in Section 23.3.

PGDATA
           Specifies the directory where the database cluster is to be stored; can be overridden using the -D
           option.

       PG_COLOR
           Specifies whether to use color in diagnostic messages. Possible values are always, auto and never.

       TZ
           Specifies the default time zone of the created database cluster. The value should be a full time zone
           name (see Section 8.5.3).

       initdb - create a new PostgreSQL database cluster

initdb can also be invoked via pg_ctlinitdb.

-Aauthmethod--auth=authmethod
           This option specifies the default authentication method for local users used in pg_hba.conf (host and
           local lines). See Section 20.1 for an overview of valid values.

           initdb will prepopulate pg_hba.conf entries using the specified authentication method for
           non-replication as well as replication connections.

           Do not use trust unless you trust all local users on your system.  trust is the default for ease of
           installation.

       --auth-host=authmethod
           This option specifies the authentication method for local users via TCP/IP connections used in
           pg_hba.conf (host lines).

       --auth-local=authmethod
           This option specifies the authentication method for local users via Unix-domain socket connections
           used in pg_hba.conf (local lines).

       -Ddirectory--pgdata=directory
           This option specifies the directory where the database cluster should be stored. This is the only
           information required by initdb, but you can avoid writing it by setting the PGDATA environment
           variable, which can be convenient since the database server (postgres) can find the data directory
           later by the same variable.

       -Eencoding--encoding=encoding
           Selects the encoding of the template databases. This will also be the default encoding of any
           database you create later, unless you override it then. The character sets supported by the
           PostgreSQL server are described in Section 23.3.1.

           By default, the template database encoding is derived from the locale. If --no-locale is specified
           (or equivalently, if the locale is C or POSIX), then the default is UTF8 for the ICU provider and
           SQL_ASCII for the libc provider.

       -g--allow-group-access
           Allows users in the same group as the cluster owner to read all cluster files created by initdb. This
           option is ignored on Windows as it does not support POSIX-style group permissions.

       --icu-locale=locale
           Specifies the ICU locale when the ICU provider is used. Locale support is described in Section 23.1.

       --icu-rules=rules
           Specifies additional collation rules to customize the behavior of the default collation. This is
           supported for ICU only.

       -k--data-checksums
           Use checksums on data pages to help detect corruption by the I/O system that would otherwise be
           silent. Enabling checksums may incur a noticeable performance penalty. If set, checksums are
           calculated for all objects, in all databases. All checksum failures will be reported in the
           pg_stat_database view. See Section 28.2 for details.

       --locale=locale
           Sets the default locale for the database cluster. If this option is not specified, the locale is
           inherited from the environment that initdb runs in. Locale support is described in Section 23.1.

           If --locale-provider is builtin, --locale or --builtin-locale must be specified and set to C or
           C.UTF-8.

       --lc-collate=locale--lc-ctype=locale--lc-messages=locale--lc-monetary=locale--lc-numeric=locale--lc-time=locale
           Like --locale, but only sets the locale in the specified category.

       --no-locale
           Equivalent to --locale=C.

       --builtin-locale=locale
           Specifies the locale name when the builtin provider is used. Locale support is described in
           Section 23.1.

       --locale-provider={builtin|libc|icu}
           This option sets the locale provider for databases created in the new cluster. It can be overridden
           in the CREATEDATABASE command when new databases are subsequently created. The default is libc (see
           Section 23.1.4).

       --pwfile=filename
           Makes initdb read the bootstrap superuser's password from a file. The first line of the file is taken
           as the password.

       -Tconfig--text-search-config=config
           Sets the default text search configuration. See default_text_search_config for further information.

       -Uusername--username=username
           Sets the user name of the bootstrap superuser. This defaults to the name of the operating-system user
           running initdb.

       -W--pwprompt
           Makes initdb prompt for a password to give the bootstrap superuser. If you don't plan on using
           password authentication, this is not important. Otherwise you won't be able to use password
           authentication until you have a password set up.

       -Xdirectory--waldir=directory
           This option specifies the directory where the write-ahead log should be stored.

       --wal-segsize=size
           Set the WAL segment size, in megabytes. This is the size of each individual file in the WAL log. The
           default size is 16 megabytes. The value must be a power of 2 between 1 and 1024 (megabytes). This
           option can only be set during initialization, and cannot be changed later.

           It may be useful to adjust this size to control the granularity of WAL log shipping or archiving.
           Also, in databases with a high volume of WAL, the sheer number of WAL files per directory can become
           a performance and management problem. Increasing the WAL file size will reduce the number of WAL
           files.

       Other, less commonly used, options are also available:

       -cname=value--setname=value
           Forcibly set the server parameter name to value during initdb, and also install that setting in the
           generated postgresql.conf file, so that it will apply during future server runs. This option can be
           given more than once to set several parameters. It is primarily useful when the environment is such
           that the server will not start at all using the default parameters.

       -d--debug
           Print debugging output from the bootstrap backend and a few other messages of lesser interest for the
           general public. The bootstrap backend is the program initdb uses to create the catalog tables. This
           option generates a tremendous amount of extremely boring output.

       --discard-caches
           Run the bootstrap backend with the debug_discard_caches=1 option. This takes a very long time and is
           only of use for deep debugging.

       -Ldirectory
           Specifies where initdb should find its input files to initialize the database cluster. This is
           normally not necessary. You will be told if you need to specify their location explicitly.

       -n--no-clean
           By default, when initdb determines that an error prevented it from completely creating the database
           cluster, it removes any files it might have created before discovering that it cannot finish the job.
           This option inhibits tidying-up and is thus useful for debugging.

       -N--no-sync
           By default, initdb will wait for all files to be written safely to disk. This option causes initdb to
           return without waiting, which is faster, but means that a subsequent operating system crash can leave
           the data directory corrupt. Generally, this option is useful for testing, but should not be used when
           creating a production installation.

       --no-instructions
           By default, initdb will write instructions for how to start the cluster at the end of its output.
           This option causes those instructions to be left out. This is primarily intended for use by tools
           that wrap initdb in platform-specific behavior, where those instructions are likely to be incorrect.

       -s--show
           Show internal settings and exit, without doing anything else. This can be used to debug the initdb
           installation.

       --sync-method=method
           When set to fsync, which is the default, initdb will recursively open and synchronize all files in
           the data directory. The search for files will follow symbolic links for the WAL directory and each
           configured tablespace.

           On Linux, syncfs may be used instead to ask the operating system to synchronize the whole file
           systems that contain the data directory, the WAL files, and each tablespace. See
           recovery_init_sync_method for information about the caveats to be aware of when using syncfs.

           This option has no effect when --no-sync is used.

       -S--sync-only
           Safely write all database files to disk and exit. This does not perform any of the normal initdb
           operations. Generally, this option is useful for ensuring reliable recovery after changing fsync from
           off to on.

       Other options:

       -V--version
           Print the initdb version and exit.

       -?--help
           Show help about initdb command line arguments, and exit.

pg_ctl(1), postgres(1), Section 20.1

PostgreSQL 17.5                                       2025                                             INITDB(1)

initdb [option...] [--pgdata | -D] directory