diff --git a/contrib/pg_upgrade/check.c b/contrib/pg_upgrade/check.c
new file mode 100644
index 891eb9a..a5f63eb
*** a/contrib/pg_upgrade/check.c
--- b/contrib/pg_upgrade/check.c
*************** report_clusters_compatible(void)
*** 148,156 ****
  	}
  
  	pg_log(PG_REPORT, "\n"
! 		   "If pg_upgrade fails after this point, you must re-initdb the new cluster\n"
! 		   "before continuing.  You will also need to remove the \".old\" suffix from\n"
! 		   "%s/global/pg_control.old.\n", old_cluster.pgdata);
  }
  
  
--- 148,155 ----
  	}
  
  	pg_log(PG_REPORT, "\n"
! 		   "If pg_upgrade fails after this point, you must re-initdb the\n"
! 		   "new cluster before continuing.\n");
  }
  
  
*************** output_completion_banner(char *deletion_
*** 198,205 ****
  	/* Did we copy the free space files? */
  	if (GET_MAJOR_VERSION(old_cluster.major_version) >= 804)
  		pg_log(PG_REPORT,
! 			   "Optimizer statistics are not transferred by pg_upgrade so consider\n"
! 			   "running:\n"
  			   "    vacuumdb --all --analyze-only\n"
  			   "on the newly-upgraded cluster.\n\n");
  	else
--- 197,204 ----
  	/* Did we copy the free space files? */
  	if (GET_MAJOR_VERSION(old_cluster.major_version) >= 804)
  		pg_log(PG_REPORT,
! 			   "Optimizer statistics are not transferred by pg_upgrade so\n"
! 			   "consider running:\n"
  			   "    vacuumdb --all --analyze-only\n"
  			   "on the newly-upgraded cluster.\n\n");
  	else
diff --git a/contrib/pg_upgrade/controldata.c b/contrib/pg_upgrade/controldata.c
new file mode 100644
index 8560d88..4c77ac9
*** a/contrib/pg_upgrade/controldata.c
--- b/contrib/pg_upgrade/controldata.c
*************** check_control_data(ControlData *oldctrl,
*** 516,526 ****
  
  
  void
! rename_old_pg_control(void)
  {
  	char		old_path[MAXPGPATH],
  				new_path[MAXPGPATH];
  
  	prep_status("Adding \".old\" suffix to old global/pg_control");
  
  	snprintf(old_path, sizeof(old_path), "%s/global/pg_control", old_cluster.pgdata);
--- 516,527 ----
  
  
  void
! disable_old_cluster(void)
  {
  	char		old_path[MAXPGPATH],
  				new_path[MAXPGPATH];
  
+ 	/* rename pg_control so old server cannot be accidentally started */
  	prep_status("Adding \".old\" suffix to old global/pg_control");
  
  	snprintf(old_path, sizeof(old_path), "%s/global/pg_control", old_cluster.pgdata);
*************** rename_old_pg_control(void)
*** 528,531 ****
--- 529,540 ----
  	if (pg_mv_file(old_path, new_path) != 0)
  		pg_log(PG_FATAL, "Unable to rename %s to %s.\n", old_path, new_path);
  	check_ok();
+ 
+ 	pg_log(PG_REPORT, "\n"
+ 		   "If you want to start the old cluster, you will need to remove\n"
+ 		   "the \".old\" suffix from %s/global/pg_control.old.\n", old_cluster.pgdata);
+ 	if (user_opts.transfer_mode == TRANSFER_MODE_LINK)
+ 		pg_log(PG_REPORT,
+ 				"Because \"link\" mode was used, the old cluster cannot be safely\n"
+ 				"started once the new cluster has been started.\n");
  }
diff --git a/contrib/pg_upgrade/pg_upgrade.c b/contrib/pg_upgrade/pg_upgrade.c
new file mode 100644
index 15b30fc..47cc683
*** a/contrib/pg_upgrade/pg_upgrade.c
--- b/contrib/pg_upgrade/pg_upgrade.c
***************
*** 43,49 ****
  #include <langinfo.h>
  #endif
  
- static void disable_old_cluster(void);
  static void prepare_new_cluster(void);
  static void prepare_new_databases(void);
  static void create_new_objects(void);
--- 43,48 ----
*************** main(int argc, char **argv)
*** 87,93 ****
  	pg_log(PG_REPORT, "\nPerforming Upgrade\n");
  	pg_log(PG_REPORT, "------------------\n");
  
- 	disable_old_cluster();
  	prepare_new_cluster();
  
  	stop_postmaster(false);
--- 86,91 ----
*************** main(int argc, char **argv)
*** 128,133 ****
--- 126,133 ----
  
  	issue_warnings(sequence_script_file_name);
  
+ 	disable_old_cluster();
+ 
  	pg_log(PG_REPORT, "\nUpgrade complete\n");
  	pg_log(PG_REPORT, "----------------\n");
  
*************** setup(char *argv0, bool live_check)
*** 176,189 ****
  }
  
  
- static void
- disable_old_cluster(void)
- {
- 	/* rename pg_control so old server cannot be accidentally started */
- 	rename_old_pg_control();
- }
- 
- 
  static void
  prepare_new_cluster(void)
  {
--- 176,181 ----
diff --git a/contrib/pg_upgrade/pg_upgrade.h b/contrib/pg_upgrade/pg_upgrade.h
new file mode 100644
index 58d5201..a954815
*** a/contrib/pg_upgrade/pg_upgrade.h
--- b/contrib/pg_upgrade/pg_upgrade.h
*************** void		create_script_for_old_cluster_dele
*** 282,289 ****
  /* controldata.c */
  
  void		get_control_data(ClusterInfo *cluster, bool live_check);
! void check_control_data(ControlData *oldctrl,
! 				   ControlData *newctrl);
  
  
  /* dump.c */
--- 282,289 ----
  /* controldata.c */
  
  void		get_control_data(ClusterInfo *cluster, bool live_check);
! void		check_control_data(ControlData *oldctrl, ControlData *newctrl);
! void		disable_old_cluster(void);
  
  
  /* dump.c */
*************** int exec_prog(bool throw_error, const ch
*** 298,304 ****
  	__attribute__((format(PG_PRINTF_ATTRIBUTE, 2, 3)));
  void		verify_directories(void);
  bool		is_server_running(const char *datadir);
- void		rename_old_pg_control(void);
  
  
  /* file.c */
--- 298,303 ----
diff --git a/doc/src/sgml/pgupgrade.sgml b/doc/src/sgml/pgupgrade.sgml
new file mode 100644
index 1373069..a27f041
*** a/doc/src/sgml/pgupgrade.sgml
--- b/doc/src/sgml/pgupgrade.sgml
***************
*** 182,188 ****
  
      <para>
       If you are using a version-specific installation directory, e.g.
!      <filename>/opt/PostgreSQL/8.4</>, you do not need to move the old cluster. The
       one-click installers all use version-specific installation directories.
      </para>
  
--- 182,188 ----
  
      <para>
       If you are using a version-specific installation directory, e.g.
!      <filename>/opt/PostgreSQL/9.1</>, you do not need to move the old cluster. The
       one-click installers all use version-specific installation directories.
      </para>
  
*************** gmake prefix=/usr/local/pgsql.new instal
*** 254,260 ****
  
      <para>
       Install any custom shared object files (or DLLs) used by the old cluster
!      into the new cluster, e.g. <filename>pgcrypto.so</filename>, whether they are from <filename>contrib</filename>
       or some other source. Do not install the schema definitions, e.g.
       <filename>pgcrypto.sql</>, because these will be upgraded from the old cluster.
      </para>
--- 254,261 ----
  
      <para>
       Install any custom shared object files (or DLLs) used by the old cluster
!      into the new cluster, e.g. <filename>pgcrypto.so</filename>, 
!      whether they are from <filename>contrib</filename>
       or some other source. Do not install the schema definitions, e.g.
       <filename>pgcrypto.sql</>, because these will be upgraded from the old cluster.
      </para>
*************** psql --username postgres --file script.s
*** 457,471 ****
          If you
          ran <command>pg_upgrade</command> <emphasis>without</> <option>--link</>
          or did not start the new server, the old cluster was not
!         modified except that an <literal>.old</> suffix was appended
!         to <filename>$PGDATA/global/pg_control</> and perhaps
!         tablespace directories. To reuse the old cluster, remove
!         the <filename>.old</> suffix
!         from <filename>$PGDATA/global/pg_control</>. and, if upgrading
!         to 8.4 or earlier, remove the tablespace directories created
!         by the upgrade and remove the <filename>.old</> suffix from
!         the tablespace directory names; then you can restart the old
!         cluster.
         </para>
        </listitem>
       </itemizedlist>
--- 458,469 ----
          If you
          ran <command>pg_upgrade</command> <emphasis>without</> <option>--link</>
          or did not start the new server, the old cluster was not
!         modified except that, if <command>pg_upgrade</command> succeeded,
!         a <literal>.old</> suffix was appended to
!         <filename>$PGDATA/global/pg_control</>.  To reuse the old
!         cluster, possibly remove the <filename>.old</> suffix from
!         <filename>$PGDATA/global/pg_control</>; you can then restart the
!         old cluster.
         </para>
        </listitem>
       </itemizedlist>
*************** psql --username postgres --file script.s
*** 582,590 ****
    </para>
  
    <para>
!    If you want to use link mode and you don't want your old cluster
     to be modified when the new cluster is started, make a copy of the
!    old cluster and upgrade that with link mode. To make a valid copy
     of the old cluster, use <command>rsync</> to create a dirty
     copy of the old cluster while the server is running, then shut down
     the old server and run <command>rsync</> again to update the copy with any
--- 580,588 ----
    </para>
  
    <para>
!    If you want to use link mode and you do not want your old cluster
     to be modified when the new cluster is started, make a copy of the
!    old cluster and upgrade that in link mode. To make a valid copy
     of the old cluster, use <command>rsync</> to create a dirty
     copy of the old cluster while the server is running, then shut down
     the old server and run <command>rsync</> again to update the copy with any