do-aging.php

<?php
    // perform filesystem aging by repetitive file creation and deletion.

    $generation_count = 2000;

    // file categories
    $q = array (
        0 => array ( // small files
            'size' => array (0, 16384),
            'create' => array (0, 70),
            'delete' => array (0, 69)
        ),
        1 => array (
            'size' => array (512*1024, 6*1024*1024),
            'create' => array (1, 10),
            'delete' => array (1, 9)
        ),
        2 => array (  // large files, videos
            'size' => array (500*1024*1024, 700*1024*1024),
            'create' => array (0, 1),
            'delete' => array (0, 1)
        )

    );

    $buffer = "a";
    for ($k = 0; $k < 20; $k ++) $buffer .= $buffer;       // $buffer is now 1 MiB

    $filenames = array();
    for ($k = 0; $k < count ($q); $k ++) $filenames[$k] = array();
    $flag_ran_out_of_space = 0;

    for ($generation = 0; $generation < $generation_count; $generation ++) {
        echo "generation ".sprintf("%4d", $generation)."\n";

        // creating files
        for ($type = 0; $type < count ($q); $type ++) {
            $count = rand ($q[$type]['create'][0], $q[$type]['create'][1]);
            $count = max ($count, 0);
            echo "   creating $count files of type $type ";
            for ($k = 0; $k < $count; $k ++) {
                $name = tempnam (".", "aging${type}_");
                $size = rand ($q[$type]['size'][0], $q[$type]['size'][1]);
                $fp = fopen ($name, "wb");
                $written = 0;
                while ($size > 0) {
                    $block_size = min ($size, 1024*1024);
                    $written = fwrite ($fp, $buffer, $block_size);
                    $size = $size - $written;
                    if (0 == $written) break;
                }
                fclose ($fp);
                $filenames[$type][] = $name;
                if (0 == $written) {
                    $flag_ran_out_of_space = 1;
                    echo "no space left."; break;
                }
                echo ".";
            }
            echo "\n";
        }

        // on first generation do not delete files
        if (0 == $generation) continue;

        // deleting files
        for ($type = 0; $type < count($q); $type ++) {
            $count = rand ($q[$type]['delete'][0], $q[$type]['delete'][1]);
            $count = max ($count, 0);
            echo "   deleting $count files of type $type ";
            for ($k = 0; $k < $count; $k ++) {
                if (count ($filenames[$type]) > 0) {
                    $key = array_rand ($filenames[$type]);
                    unlink ($filenames[$type][$key]);
                    unset ($filenames[$type][$key]);
                    echo ".";
                }
            }
            echo "\n";
        }
    }

    if ($flag_ran_out_of_space) {
        echo "Warning: there was time when no space was left.\n";
    }