[svnbook] r3868 committed - * src/en/book/ch05-repository-admin.xml...

[svnbook at googlecode.com]

Revision: 3868
Author:   cmpilato at gmail.com
Date:     Thu Jun 30 11:40:28 2011
Log:      * src/en/book/ch05-repository-admin.xml
   (svn.reposadmin.maint.diskspace.deltas): Mention rep-sharing,
     finishing issue #16 ("New 1.6 feature: FS representation sharing").

http://code.google.com/p/svnbook/source/detail?r=3868

Modified:
  /trunk/src/en/book/ch05-repository-admin.xml

=======================================
--- /trunk/src/en/book/ch05-repository-admin.xml	Tue Dec 14 09:05:20 2010
+++ /trunk/src/en/book/ch05-repository-admin.xml	Thu Jun 30 11:40:28 2011
@@ -1498,25 +1498,33 @@
        <sect3 id="svn.reposadmin.maint.diskspace.deltas">
          <title>How Subversion saves disk space</title>

-        <para>To keep the repository small,
-          Subversion uses <firstterm>deltification</firstterm> (or
-          deltified storage) within the repository
-          itself.  Deltification involves encoding the representation
-          of a chunk of data as a collection of differences against
-          some other chunk of data.  If the two pieces of data are
-          very similar, this deltification results in storage savings
-          for the deltified chunk—rather than taking up space
-          equal to the size of the original data, it takes up only
-          enough space to say, <quote>I look just like this other
-          piece of data over here, except for the following couple of
-          changes.</quote>  The result is that most of the repository
-          data that tends to be bulky—namely, the contents of
-          versioned files—is stored at a much smaller size than
-          the original full-text representation of that
-          data.  And for repositories created with Subversion 1.4 or
-          later, the space savings are even better—now those
-          full-text representations of file contents are themselves
-          compressed.</para>
+        <para>To keep the repository small, Subversion uses
+          <firstterm>deltification</firstterm> (or delta-based storage)
+          within the repository itself.  Deltification involves
+          encoding the representation of a chunk of data as a
+          collection of differences against some other chunk of data.
+          If the two pieces of data are very similar, this
+          deltification results in storage savings for the deltified
+          chunk—rather than taking up space equal to the size of
+          the original data, it takes up only enough space to
+          say, <quote>I look just like this other piece of data over
+          here, except for the following couple of changes.</quote>
+          The result is that most of the repository data that tends to
+          be bulky—namely, the contents of versioned
+          files—is stored at a much smaller size than the
+          original full-text representation of that data.</para>
+
+        <para>While deltified storage has been a part of Subversion's
+          design since the very beginning, there have been additional
+          improvements made over the years.  Subversion repositories
+          created with Subversion 1.4 or later benefit from
+          compression of the full-text representations of file
+          contents.  Repositories created with Subversion 1.6 or later
+          further enjoy the disk space savings afforded by
+          <firstterm>representation sharing</firstterm>, a feature
+          which allows multiple files or file revisions with identical
+          file content to refer to a single shared instance of that data
+          rather than each having their own distinct copy thereof.</para>

          <note>
            <para>Because all of the data that is subject to