Preface

1.1. Abstract

IREn InGrid is a server-based product for shared document formatting. It accepts XSL-FO documents over the network and formats them by distributing the formatting tasks among multiple formatters that may run locally or on other computers in the network. Regular users publish customized documents in high volumes and varied formats. The server is accessed via straightforward controls. The users may customize server operation for their workflow.

IREn InGrid is a direct replacement of EnMasse. It is completely backward compatible with EnMasse, i.e. it accepts the same configuration files and supports the same working modes while providing significantly better performance.

Additionally, IREn InGrid provides with REST API.

1.2. A Bird's Eye View

Computation-heavy processes, like XML transformation or rendering XSL-FO to PDF, require significant resources and take more time to complete if ran on a local machine.

The conservative approach to this problem is using multiple-core and multiple-CPU configurations with server-grade amounts of memory. This introduces the need of effective and scalable task management tools to distribute the rendering tasks between the cores, detect and retry on failures, balance the load, unify the logging, compute statistics, and so on.

While multiple-core systems may be sufficient for a certain amount of rendered documents per time unit, sooner or later, any upgrade bumps into physical limits of the architecture. A really scalable solution would require the synergy of rendering engines running on multiple computers across the network. Using multiple computers, the rendering cores can achieve a data throughput at the current level of technology permits; and the price for stock single-CPU PCs is low enough to have sufficient resources to meet any business needs.

This approach also helps reliability and fail-tolerance of the grid; when the rendering engines are constantly online, the load is evenly distributed; in case when a node is down due to hardware failure or being upgraded, the entire system still processes all requests, preserves data, however, at the cost of the degraded performance. This is a well-known but not an easy task; and to really use the synergy power of the grid computing as it is known, you must resolve this issue.

RenderX IREn is a rendering engine that creates elegantly formatted print-ready template-based documents. In many deployments, it produces hundreds of thousands of documents on demand. For example:

• A bank printing monthly statements,

• a technical authoring department preparing documentation in twenty languages for electronic and hard-copy delivery,

• numerous users filing a loan application form on-line at the same time and requesting their own copies concurrently, in a printable form.

These are just a few examples. While IREn is based on an optimized and highly-performant code, the business needs a way to scale up the performance to be able to handle a constantly growing load.

IREn InGrid solves this problem for you. For an end user or an application programmer, it acts as a single access point. Through a shared folder, a Web form or a network connection (locally on the LAN, or across the Internet), IREn InGrid accepts document processing requests and sends them to one of the IREn formatting engines running locally or on several computers in the local network, then delivers formatted documents back to the user. IREn InGrid also monitors the performance of each formatting engines, notices when they go down and are restored, and re-adjusts the distribution of the requests according to the workload. When a server fails in the midst of processing a request, IREn InGrid re-submits the request to a different server; thus the only impact is a slightly increased response time for that particular document. This provides the reliability of the entire service needed in today's world.

IREn InGrid is both opaque and transparent. On one hand, it provides with a single point abstraction so that there is no need to worry about the number of engines running, or about their load; IREn InGrid dispatches requests to the most appropriate node. On the other hand, both the access point and the processing engines have standard, embedded servers. The system administrator can instantly check the status of the nodes in the grid, identify problems and take an appropriate action. An IREn InGrid access point takes little memory overhead and processing time, it can be deployed on a busy Intranet server, or even on a consumer-grade workstation and, as long as the processing engines run on separate machines, it does not affect the performance or throughput of the grid.

For debugging purposes, audit, and performance tuning, IREn InGrid provides a logging facility. One can adjust the verbosity of the logging, or completely turn it off. The log files are easy to read and to process by programs.

IREn InGrid runs on a wide range of hardware and operating systems, easy to install and requires a little maintenance.