* Portions Copyright (c) 1996-2004, PostgreSQL Global Development Group
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.176 2004/11/05 17:10:56 petere Exp $
+ * $PostgreSQL: pgsql/src/backend/access/transam/xlog.c,v 1.177 2004/11/17 02:22:54 neilc Exp $
  *
  *-------------------------------------------------------------------------
  */
        ereport(ERROR,
                (errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
                 (errmsg("must be superuser to run a backup"))));
+
+   if (!XLogArchivingActive())
+       ereport(ERROR,
+               (errcode(ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE),
+                (errmsg("WAL archiving is not configured"),
+                (errhint("archive_command must be defined before "
+                         "online backups can be safely made.")))));
+
    backupidstr = DatumGetCString(DirectFunctionCall1(textout,
                                             PointerGetDatum(backupid)));