Estimation of capacity for users of an IRC server based on memory usage and bandwidth using ChatGPT

1. Question

Assume a server with 2GB of memory and a bandwidth of 150Mbit/second, which runs a minimal Linux operating System, such as Alpine Linux, an IRC server, eg ERGO chat, and an IRC web client, eg TheLounge. All connections use TLS encryption.

Questions:

  1. How much memory is available for handling Internet Relay Chat (IRC) traffic, if the web client is not used by any users? How many IRC users can simultaneously be active on such a server?
  2. How much memory is available for handling Internet Relay Chat (IRC) traffic, if the web client is used by all users? How many IRC users can simultaneously be active on such a server?

Please start by first estimating a plausible memory usage per IRC user connecting with an external IRC client to the server.

2. ANSWER

Let’s break this down step by step.

Step 1: Estimating Memory Usage per IRC User (External Client Only)

Memory usage per IRC user depends on various factors, including the efficiency of the IRC server software, the number of channels a user joins, and the number of messages processed. Based on benchmarks and estimates from various IRC daemons:

  • A lightweight IRC server like Ergo typically uses 5–10 MB RAM as a base footprint.
  • Each IRC user connection (using an external IRC client) consumes around 50–200 KB RAM, depending on activity.
    • Idle users: ~50 KB
    • Moderately active users: ~100 KB
    • Very active users (many channels, messages): ~200 KB

We assume an average 100 KB (0.1 MB) per user for a reasonable estimate.


Step 2: Estimating Available Memory for IRC Traffic (Without Web Client)

Total system memory: 2 GB (≈ 2048 MB)

System & Server Memory Usage

Component Estimated Memory Usage
Alpine Linux (minimal OS) ~100 MB
Ergo IRC Server (base footprint) ~10 MB
TLS encryption overhead ~20 MB
Other system processes (networking, logging, etc.) ~70 MB
Available for IRC traffic ≈ 1848 MB

User Capacity Without Web Client

  • Available memory for IRC traffic: 1848 MB
  • Memory per user (external IRC client): 0.1 MB
  • Max users ≈ 1848 / 0.1 = 18,480 users

Given that real-world memory fragmentation and peak loads exist, a safe estimate would be around 15,000 active IRC users.


Step 3: Estimating Available Memory for IRC Traffic (With Web Client)

TheLounge is an IRC web client that runs a Node.js-based process.

Additional Memory Usage When Using TheLounge

Component Estimated Memory Usage
TheLounge base footprint ~100 MB
Per-user memory usage in TheLounge ~30 MB

Available Memory for IRC Traffic

Component Memory Usage
Alpine Linux 100 MB
Ergo IRC Server 10 MB
TLS encryption overhead 20 MB
TheLounge (base footprint) 100 MB
Other system processes 70 MB
Available for IRC traffic & web users ≈ 1748 MB

User Capacity With Web Client

  • Each IRC user now requires: 100 KB (IRC server) + 30 MB (TheLounge) ≈ 30.1 MB
  • Available memory: 1748 MB
  • Max users ≈ 1748 / 30.1 ≈ 58 users

A safe estimate would be around 50 users using TheLounge simultaneously.


Step 4: Bandwidth Check

Bandwidth limit: 150 Mbps (18.75 MB/s)

  • IRC is extremely bandwidth-light; text-based communication uses only a few KB per second per user.
  • TheLounge does introduce additional HTTP overhead, but even with 50 active web users, the bandwidth is not a bottleneck.

Final Answers

  1. Without TheLounge: ~15,000 IRC users can be supported.
  2. With TheLounge: ~50 IRC users can be supported.

Would you like any further optimizations or considerations?

Reference

1) Igl, W. (2025). Prompt “Assume a server with 2GB of memory and a bandwidth of 150Mbit/second, which runs a minimal Linux operating System, such as Alpine Linux, an IRC server, eg ERGO chat, and an IRC web client, eg TheLounge. All connections use TLS encryption. Questions: How much memory is available for handling Internet Relay Chat (IRC) traffic, if the web client is not used by any users? How many IRC users can simultaneously be active on such a server? How much memory is available for handling Internet Relay Chat (IRC) traffic, if the web client is used by all users? How many IRC users can simultaneously be active on such a server? Please start by first estimating a plausible memory usage per IRC user connecting with an external IRC client to the server.”, Retrieved 2025-02-03, from https://chatgpt.com

 

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