Add info about using rsync to make base backups. Per report from

Jeff Frost, it may be necessary to ignore specific exit codes.

diff --git a/doc/src/sgml/backup.sgml b/doc/src/sgml/backup.sgml
index 74f3add15c3d0b5749aabc08e7b92ce839152824..c954816936d9739650969264a3b7f861e86d65da 100644 (file)
--- a/doc/src/sgml/backup.sgml
+++ b/doc/src/sgml/backup.sgml
@@ -1,5 +1,5 @@
 
 
  Backup and Restore
@@ -677,12 +677,20 @@ SELECT pg_stop_backup();
    
 
    
-    Some versions of GNU tar consider it an error if a file
-    is changed while tar is copying it.  This case is normal,
-    and not an error, when taking a base backup of an active database.
-    Since ignoring all errors from tar would be unwise,
-    you should either manually inspect tar's messages or
-    else use a different backup tool that does not complain about this case.
+    Some backup tools that you might wish to use emit warnings or errors
+    if the files they are trying to copy change while the copy proceeds.
+    This situation is normal, and not an error, when taking a base backup of
+    an active database; so you need to ensure that you can distinguish
+    complaints of this sort from real errors.  For example, some versions
+    of rsync return a separate exit code for vanished
+    source files, and you can write a driver script to accept this exit
+    code as a non-error case.  Also,
+    some versions of GNU tar consider it an error if a file
+    is changed while tar is copying it.  There does not seem
+    to be any very convenient way to distinguish this error from other types
+    of errors, other than manual inspection of tar's messages.
+    GNU tar is therefore not the best tool for making base
+    backups.