diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml index 854b5fde41c..06f064e1a6f 100644 --- a/doc/src/sgml/backup.sgml +++ b/doc/src/sgml/backup.sgml @@ -943,6 +943,21 @@ SELECT pg_stop_backup(); (These files can confuse pg_ctl.) + + It is often a good idea to also omit from the backup dump the files + within the cluster's pg_replslot/ directory, so that + replication slots that exist on the master do not become part of the + backup. Otherwise, the subsequent use of the backup to create a standby + may result in indefinite retention of WAL files on the standby, and + possibly bloat on the master if hot standby feedback is enabled, because + the clients that are using those replication slots will still be connecting + to and updating the slots on the master, not the standby. Even if the + backup is only intended for use in creating a new master, copying the + replication slots isn't expected to be particularly useful, since the + contents of those slots will likely be badly out of date by the time + the new master comes on line. + + It's also worth noting that the pg_start_backup function makes a file named backup_label in the database cluster