mirror of https://github.com/BOINC/boinc.git
99 lines
3.1 KiB
PHP
99 lines
3.1 KiB
PHP
<?php
|
|
|
|
require_once("docutil.php");
|
|
|
|
page_head("Hierarchical upload/download directories");
|
|
|
|
echo "
|
|
The data server for a large project,
|
|
may store 100Ks or millions of files at any given point.
|
|
If these files are stored in 'flat' directories
|
|
(project/download and project/upload)
|
|
the data server may spend a lot of CPU time searching directories.
|
|
If you see a high CPU load average,
|
|
with a lot of time in kernel mode,
|
|
this is probably what's happening.
|
|
|
|
<p>
|
|
The solution is to use
|
|
<b>hierarchical upload/download directories</b>.
|
|
To do this, include the line
|
|
".html_text("
|
|
<uldl_dir_fanout>1024</uldl_dir_fanout>
|
|
")."
|
|
in your <a href=configuration.php>config.xml file</a>
|
|
(this is the default for new projects).
|
|
|
|
<p>
|
|
This causes BOINC to use hierarchical upload/download directories.
|
|
Each directory will have a set of 1024 subdirectories, named 0 to 3ff.
|
|
Files are hashed (based on their filename) into these directories.
|
|
|
|
<p>
|
|
The hierarchy is used for input and output files only.
|
|
Executables and other application version files are
|
|
in the top level of the download directory.
|
|
|
|
<p>
|
|
This affects your project-specific code in a couple of places.
|
|
First, your work generator must put input files in
|
|
the right directory before calling <a href=tools_work.php>create_work()</a>.
|
|
To do this, it can use the function
|
|
".html_text("
|
|
int dir_hier_path(
|
|
const char* filename, const char* root, int fanout, char* result,
|
|
bool make_directory_if_needed=false
|
|
);
|
|
")."
|
|
This takes a name of the input file
|
|
and the absolute path of the root of the download hierarchy
|
|
(typically the download_dir element from config.xml)
|
|
and returns the absolute path of the file in the hierarchy.
|
|
Generally make_directory_if_needed should be set to true:
|
|
this creates a fanout directory if needed
|
|
to accomodate a particular file.
|
|
|
|
<p>
|
|
Secondly, your validator and assimilator should call
|
|
".html_text("
|
|
int get_output_file_path(RESULT const& result, string& path);
|
|
")."
|
|
to get the paths of output files in the hierarchy.
|
|
If your application has multiple output files,
|
|
you'll need to generalize this function.
|
|
|
|
<p>
|
|
A couple of utility programs are available:
|
|
".html_text("
|
|
dir_hier_move src_dir dst_dir fanout
|
|
dir_hier_path filename
|
|
")."
|
|
<code>dir_hier_move</code> moves all files from src_dir (flat)
|
|
into dst_dir (hierarchical with the given fanout).
|
|
<code>dir_hier_path</code>, given a filename,
|
|
prints the full pathname of that file in the hierarchy.
|
|
|
|
|
|
<h2>Transitioning from flat to hierarchical directories</h2>
|
|
<p>
|
|
If you are operating a project with flat directories,
|
|
you can transition to a hierarchy as follows:
|
|
<ul>
|
|
<li> Stop the project and add <uldl_dir_fanout> to config.xml.
|
|
You may want to locate the hierarchy root at a new place
|
|
(e.g. download/fanout); in this case update the
|
|
<download_dir> element of config.xml,
|
|
and add the element
|
|
".html_text("
|
|
<download_dir_alt>old download dir</download_dir_alt>
|
|
")."
|
|
This causes the file deleter to check both old and new locations.
|
|
|
|
<li> Use dir_hier_move to move existing upload files to a hierarchy.
|
|
<li> Start the project, and monitor everything closely for a while.
|
|
</ul>
|
|
";
|
|
|
|
page_tail();
|
|
?>
|