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Diffstat (limited to 'doc/src')
| -rw-r--r-- | doc/src/sgml/ref/pg_basebackup.sgml | 42 |
1 files changed, 42 insertions, 0 deletions
diff --git a/doc/src/sgml/ref/pg_basebackup.sgml b/doc/src/sgml/ref/pg_basebackup.sgml index 05d5bedef93..c654a364124 100644 --- a/doc/src/sgml/ref/pg_basebackup.sgml +++ b/doc/src/sgml/ref/pg_basebackup.sgml @@ -64,6 +64,48 @@ PostgreSQL documentation better from a performance point of view to take only one backup, and copy the result. </para> + + <para> + <application>pg_basebackup</application> can make a base backup from + not only the master but also the standby. To take a backup from the standby, + set up the standby so that it can accept replication connections (that is, set + <varname>max_wal_senders</> and <xref linkend="guc-hot-standby">, + and configure <link linkend="auth-pg-hba-conf">host-based authentication</link>). + You will also need to enable <xref linkend="guc-full-page-writes"> on the master. + </para> + + <para> + Note that there are some limitations in an online backup from the standby: + + <itemizedlist> + <listitem> + <para> + The backup history file is not created in the database cluster backed up. + </para> + </listitem> + <listitem> + <para> + There is no guarantee that all WAL files required for the backup are archived + at the end of backup. If you are planning to use the backup for an archive + recovery and want to ensure that all required files are available at that moment, + you need to include them into the backup by using <literal>-x</> option. + </para> + </listitem> + <listitem> + <para> + If the standby is promoted to the master during online backup, the backup fails. + </para> + </listitem> + <listitem> + <para> + All WAL records required for the backup must contain sufficient full-page writes, + which requires you to enable <varname>full_page_writes</> on the master and + not to use the tool like <application>pg_compresslog</> as + <varname>archive_command</> to remove full-page writes from WAL files. + </para> + </listitem> + </itemizedlist> + </para> </refsect1> <refsect1> |