pg_upgrade: document link options

Document that tablespaces and pg_xlog can be on different file systems
for pg_upgrade --link mode.
Backpatch to 9.3.

diff --git a/doc/src/sgml/pgupgrade.sgml b/doc/src/sgml/pgupgrade.sgml
index 62856f1df81dd34e7fb55e6c07facfcaf28ccb7f..f2d2d75af39c9ca41c2559b2abe2fea6b239514c 100644 (file)
--- a/doc/src/sgml/pgupgrade.sgml
+++ b/doc/src/sgml/pgupgrade.sgml
@@ -336,7 +336,8 @@ NET STOP pgsql-8.3  (<productname>PostgreSQL</> 8.3 and older used a different s
      copying), but you will not be able to access your old cluster
      once you start the new cluster after the upgrade.  Link mode also
      requires that the old and new cluster data directories be in the
-     same file system.  See <literal>pg_upgrade --help</> for a full
+     same file system.  (Tablespaces and <filename>pg_xlog</> can be on
+     different file systems.)  See <literal>pg_upgrade --help</> for a full
      list of options.
     </para>