[svnbook commit] r2925 - trunk/src/en/book

[cmpilato]

Author: cmpilato
Date: Sat Dec 15 20:27:18 2007
New Revision: 2925

Log:
Finish Trac ticket #82 by adding a bit about fsfs-reshard.py.

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

Modified: trunk/src/en/book/ch05-repository-admin.xml
==============================================================================
--- trunk/src/en/book/ch05-repository-admin.xml	(original)
+++ trunk/src/en/book/ch05-repository-admin.xml	Sat Dec 15 20:27:18 2007
@@ -1289,6 +1289,47 @@
       </sect3>
 
       <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
+      <sect3 id="svn.reposadmin.maint.tk.fsfsreshard">
+        <title>fsfs-reshard.py</title>
+
+        <para>While not an official member of the Subversion
+          toolchain, the <command>fsfs-reshard.py</command> script
+          (found in the <filename>tools/server-side</filename>
+          directory of the Subversion source distribution) is a useful
+          performance tuning tool for administrators of FSFS-backed
+          Subversion repositories.  FSFS repositories contain files
+          which describe the changes made in a single revision, and
+          files which contain the revision properties associated with
+          a single revision.  Repositories created in versions of
+          Subversion prior to 1.5 keep these files in two
+          directories—one for each type of file.  As new
+          revisions are committed to the repository, Subversion drops
+          more files into these two directories, and over time, the
+          number of these files in each directory can grow to be quite
+          large.  Unfortunately, this can cause performance problems
+          on many operating systems.</para>
+
+        <para>Subversion 1.5 creates FSFS-backed repositories using a
+          slightly modified layout in which the contents of these two
+          directories are <firstterm>sharded</firstterm>, or scattered
+          across several subdirectories.  This can greatly reduce the
+          time it takes the system to locate any one of these files,
+          and therefore increases the overall performance of
+          Subversion when reading from the repository.  The number of
+          subdirectories used to house these files is configurable,
+          though, and that's where
+          <filename>fsfs-reshard.py</filename> comes in.  This script
+          reshuffles the repository's file structure into a new
+          arrangement which reflects the requested number of sharding
+          subdirecties.  This is especially useful for converting an
+          older Subversion repository into the new Subversion 1.5
+          sharded layout (which Subversion will not automatically do
+          for you), or for fine-tuning an already-sharded
+          repository.</para>
+
+      </sect3>
+
+      <!-- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -->
       <sect3 id="svn.reposadmin.maint.tk.bdbutil">
         <title>Berkeley DB Utilities</title>