Index: doc/src/sgml/wal.sgml
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RCS file: /cvsroot/pgsql/doc/src/sgml/wal.sgml,v
retrieving revision 1.53
diff -c -c -r1.53 wal.sgml
*** doc/src/sgml/wal.sgml	2 May 2008 19:52:37 -0000	1.53
--- doc/src/sgml/wal.sgml	6 Dec 2008 21:32:59 -0000
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*** 135,140 ****
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      roll-forward recovery, also known as REDO.)
     </para>
  
+    <tip>
+     <para>
+      Because <acronym>WAL</acronym> restores database file
+      contents after a crash, it is not necessary to use a
+      journaled filesystem;  in fact, journaling overhead can
+      reduce performance.  For best performance, turn off
+      <emphasis>data</emphasis> journaling as a filesystem mount
+      option, e.g. use <literal>data=writeback</> on Linux.
+      Meta-data journaling (e.g.  file creation and directory
+      modification) is still desirable for faster rebooting after
+      a crash.
+     </para>
+    </tip>
+ 
+ 
     <para>
      Using <acronym>WAL</acronym> results in a
      significantly reduced number of disk writes, because only the log