PHP s3分段上传内存问题

Question

我有代码，假设将8GB文件上传到服务器。我遇到的问题似乎是内存问题，因为我的服务器只有4GB的内存。我上传的脚本是：

 $s3 = S3Client::factory(array(
                        'credentials' => $credentials
                ));;

                        // 2. Create a new multipart upload and get the upload ID.
                    $response = $s3->createMultipartUpload(array(
                        'Bucket' => $bucket,
                        'Key'    => $obect,
                        //'Body'   => (strlen($body) < 1000 && file_exists($body)) ? Guzzle\Http\EntityBody::factory(fopen($body, 'r+')) : $body,
                        'ACL'    => $acl,
                        'ContentType' => $content_type,
                        'curl.options' => array(
                                CURLOPT_TIMEOUT => 12000,
                        )
                    ));

                        $uploadId = $response['UploadId'];

                        // 3. Upload the file in parts.
                        $file = fopen($body, 'r');
                        $parts = array();
                        $partNumber = 1;

                        while (!feof($file)) {
                            $result = $s3->uploadPart(array(
                                'Bucket'     => $bucket,
                                'Key'        => $obect,
                                'UploadId'   => $uploadId,
                                'PartNumber' => $partNumber,
                                'Body'       => fread($file, 10 * 1024 * 1024),
                            ));
                            $parts[] = array(
                                'PartNumber' => $partNumber++,
                                'ETag'       => $result['ETag'],
                            );
                        }

  $result = $s3->completeMultipartUpload(array(
                            'Bucket'   => $bucket,
                            'Key'      => $obect
                            ,
                            'UploadId' => $uploadId,
                            'Parts'    => $parts,
                        ));

                        $url = $result['Location'];

                        return true;
                } catch (Aws\Exception\S3Exception $e) {
                        error_log($e -> getMessage() . ' ' . $e -> getTraceAsString());
                        return false;
                } catch (Exception $e) {
                        error_log($e -> getMessage() . ' ' . $e -> getTraceAsString());
                        return false;
                }

以前有人遇到过这个问题吗？我该如何解决内存问题？