Description:
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Purpose: move a file from local mount to a GlusterFS mount.
File: 16MB XML.

Vanilla PHP operation: use `rename()` to move the file.
Linux command: shell_exec("mv '$sourcePath' '$targetPath'")

Note: My glusterFS mount has a terrible performance at the moment, writes usually around 2MB/s, so it is making a good testing environment for read/write operations.

Result:
- PHP rename() takes about 56.2257 seconds to move the file.
- Linux command via shell_exec takes 15.8680s.


The latter takes 3.5433 less time than PHP's rename().

Test script:
---------------
$path1 = '/tmp/1220631606.xliff';
$path2 = '/gluster_mount/'.rand();

$start = microtime(true);
rename($path1, $path2);
$end = microtime(true);

echo 'rename time: '.($end-$start).PHP_EOL;

$start = microtime(true);
shell_exec("mv '".$path1."' '".$path2."'");
$end = microtime(true);

echo 'shell_exec time: '.($end-$start).PHP_EOL;