Update sparse documentation

diff --git a/docs/manuals/en/main/fileset.tex b/docs/manuals/en/main/fileset.tex
index 3d53156464c118921e0502641bb28bc72fa5d28d..3bf78b6304341d7a3c6dfc222ad2a1d999953103 100644 (file)
--- a/docs/manuals/en/main/fileset.tex
+++ b/docs/manuals/en/main/fileset.tex
@@ -517,9 +517,9 @@ Change: 2005-11-06 12:36:48.000000000 +0100
    ndbm.  The default is {\bf no}, so no checks are made for sparse files.
    You may specify {\bf sparse=yes} even on files that are not sparse file.
    No harm will be done, but there will be a small additional overhead to
-   check for buffers of all zero, and a small additional amount of space on
-   the output archive will be used to save the seek address of each
-   non-zero record read.
+   check for buffers of all zero, and if there is a 32K block of all zeros
+   (see below), that block will become a hole in the file, which 
+   may not be desirable if the original file was not a sparse file.
 
    {\bf Restrictions:} Bacula reads files in 32K buffers.  If the whole
    buffer is zero, it will be treated as a sparse block and not written to
@@ -547,6 +547,9 @@ Change: 2005-11-06 12:36:48.000000000 +0100
    benchmark the difference or set sparse for only those files that are
    really sparse.
 
+   You probably should not use this option on files or raw disk devices
+   that are not really sparse files (i.e. have holes in them).
+
 \label{readfifo}
 \item [readfifo=yes\vb{}no]
 \index[dir]{readfifo}