WebMelody: Sonification of Web servers

Maria Barra    Tania Cillo     Antonio De Santis 
Umberto Ferraro Petrillo     Alberto Negro   Vittorio Scarano
Dipartimento di Informatica ed Applicazioni
Università di Salerno
Baronissi (Salerno) 84081 -- Italy

1 - Introduction

WWW servers are growing in size, complexity and workload. HTTP requests are logged to files and, later, analyzed by the Webmaster so that the information can provide useful hints on tuning and/or malfunctioning in the WWW server. These log files are huge and the analysis is greatly helped by software programs that perform statistics on such huge amount of data, grouped by several criteria (time, location, Internet domain name, etc.).
Monitoring a WWW server is, usually, an off-line activity: performed on a regular basis, or prompted by evident malfunctioning. We argue that it is important to provide an effective, efficient way to monitor in real-time the behaviour of the server.
In this paper we present a novel technique to monitor the behaviour of the WWW server by associating sounds to events describing the server activity. The sounds are carefully chosen so that they form a "natural" background music: music should not engage the listener and should not disturb his/her daily activities. Our scenario is that "server music" is going to substitute (by masquerading) the background noises (normally present in the workplace and not recognized) as a low-volume radio does.

2 - Our Technique

Using nonspeech audio to convey information (or sonification), is particularly useful when there is an abudance of data to be considered. The "ticking" of a Geiger counter as well as sonar is well known since decades as well as using sounds to enable blind scientists to examine experimental data via an auditory presentation ([Lunney et al. (1990)]) or to troubleshoot intermittent network connections [Muuss].
WWW servers generate log files with information about each single HTTP request and the response. Many servers allow log data to be stored in a proprietary format (like Apache module mod_log_config) and proposals like the Extended Log File Format are studied [Hallam-Baker (1999)] to add an extensible logging mechanism.
Logfiles grow quickly to hundred of megabytes, making the analysis possible only with off-line tools (known as Log Analyzers) to present log data in a synthetic and coherent shape.

We propose to use sonification as a technique to monitor the correct functioning of the WWW server. The main positive characteristic of our technique is that it allows, in real time, to "feel" several server parameters at once while it is non-obtrusive with respect to normal daily activities. At the same time, sonification can be an efficient solution to allow on-line monitoring of the large amount of log data that are available.
The technique to use sounds to express and interpret (raw) data is non-obtrusive: the webmaster can perceive the server behavior and execute other tasks at the same time. The webmaster can have this sound as "background music" acting as a support for providing auxiliary information. This information can quickly redirect the focus of the Webmaster to the problem whenever needed so that he can take appropriate actions.

Sonification allows to convey an interpretation of a large amount of data, since all requests are analyzed and, eventually, "played" in real-time. In this way, while monitoring the behaviour, the webmaster can avoid to rely exclusively on off-line analysis of the log files that provide, indeed, accurate and entrusted statistics but that are not timely. Finally, sonification could join together the manyfold aspects of a Web server that one wants to monitor.
We envision several real-life situations where a real-time, and still non-completely absorbing, tool can help the Webmaster. By monitoring the WWW server behaviour via sonification the Webmaster can:

The sonification technique (and our tool WebMelody) is not meant to substitute off-line analysis but is, instead, devoted to ideally complement the log analyzers by giving the immediate perception of what is going on to the webmaster. Then, if necessary, the webmaster can study logfiles with the log analyzers to pinpoint problems and provide solutions.

Part of our research was devoted to find an adequate musical representation of the behaviour of a WWW server. Our goal was to provide sounds that go beyond the simple alarms, trying at the same time to offer an aestethic connotation to sounds that lay on the borderline between music and background noises. The WebMelody prototype is provided with sounds with such characteristics that allow to listen to the music for a long time without diverting the user from the focus of his/her work.
Our musical work is based on the experiences of this century in the field of the "applied music" such as Luigi Russolo (early XX century's futurism), Edgar Varese (1958) and (more recently) John Cage. In WebMelody, we tried to avoid to configure harmonic-tonal fields as well as rithmic references that are potentionally able to attract the focus of the users by leveraging on their mnemonic and musical (personal) capabilities.

3 - WebMelody: the architecture

WebMelody is a distributed, versatile (easily configurable) and portable system that allows WWW server (Apache) monitoring via sonification. The architecture of WebMelody consists of three components: the sonification Apache modules mod_musical_log and mod_counter, the Collector server and the WebPlayer application.

The sonification modules are inserted into an Apache WWW server and are responsible for sending data to the Collector upon arrival and serving of HTTP requests. These modules can filter events as specified in the appropriate configuration directives of the Apache WWW server.
The Collector is a Java application that works as middle layer: it buffers the events provided by the Web server(s), parses them and can monitor load and throughput of the Web server as well as analyze the events that must be played only if a treshold is passed. Then, a command string specifing the sounds to be played is produced and then sent to the WebPlayer(s) that holds the sound files corresponding to each event.

More details on the WebMelody system can be found at the Project Home Page at http://isis.dia.unisa.it/SONIFICATION. The full paper describing the architecture in greater detail is at http://isis.dia.unisa.it/SONIFICATION/sonification.html as well as an MP3 demo (http://isis.dia.unisa.it/SONIFICATION/web.mp3).


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