Ask any DevOps engineer how to back up a server, and they'll say "home directory, config files, databases." Standard playbook. Works for web apps, works for databases, works for most cloud workloads.
Ask them how to back up an AI agent, and suddenly nobody has a good answer. Because an agent isn't a config file with a database attached — it's a full Linux system whose state scatters across /usr, /var, /etc, and /root in ways that standard backup tools never expect.
This post walks through real filesystem data from a live Hermes agent that ran speed-runs over two weeks. The numbers may surprise you.
After one week of basic agent work, we measured the filesystem changes from a clean Debian 12 install:
504.6M ./usr 43.3M ./var 448.9M ./root 54.0K ./etc 996.8M total
A home-directory-only backup (/root) captures 448.9 MB — 45% of what changed. Already missing over half the agent's state.
Then we ran the agent through several speed-runs: Hermes Agent setup, competitor profiling, cold email configuration, Odoo integration, mobile.de research scraping. After all setups:
4.3G ./usr ← 8.5× growth 487.0M ./var ← 11.2× growth 2.1G ./root ← 4.7× growth 1.9M ./etc ← 35× growth 6.8G total ← 6.8× growth
Now a home-dir-only backup captures 2.1 GB (31%) — meaning 69% of the agent's state lives outside its home directory.
The 69% problem: If you back up only /root and restore, your agent comes back with its config files and skills — but with no Hermes runtime, no Python packages, no Node modules, no HuggingFace models, no system dependencies. It won't even start.
Here's the breakdown of what drives an agent's storage footprint and where it scatters:
| Location | Size | What It Is | Trigger |
|---|---|---|---|
/usr/local/lib |
2.3 GB | Hermes runtime, node_modules, Python 3.11 libs | Hermes installation |
/root/.npm/_cacache |
390 MB | npm package cache | Node.js tooling |
/root/.hermes |
412 MB | 19 skills, 1 plugin, cron jobs, memories, config | All speed-runs |
/root/.cache/huggingface |
142 MB | HuggingFace model weights | STT / model downloads |
/root/.cache/uv |
186 MB | UV Python package cache | Hermes venv management |
/var/cache/apt |
379 MB | Debian package cache | System dependencies |
/var/lib/apt |
80 MB | APT package state | System dependencies |
/usr/local/bin |
28 MB | hermes CLI, other executables | Hermes installation |
/root/.config |
475 KB | App configurations | Misc tools |
/etc |
1.9 MB | System config (hostname, apt sources, etc.) | OS configuration |
Total blog content created during this period: 5 posts (Odoo, Hermes setup guide, competitor profiling, cold email, mobile.de research) — and those 5 posts alone drove the system past 1 GB.
The sprawl isn't static — it compounds. Each new skill adds Python or Node dependencies in /usr/local. Each new cron job writes logs and state. Each new model download caches weights in /root/.cache. Each system package lands in /var.
Look at the trend:
/root/root/usr packages, more /var data, more scattered caches
A "backup your home directory" strategy doesn't just miss some data — it misses a growing majority of it. Restoring from a home-dir backup would give you your .hermes skills and config back, but Hermes itself, all its runtime dependencies, system packages, and model weights would be gone. Your agent would boot to a broken environment.
The only way to guarantee an agent restores to a working state is to back up its entire filesystem — not just the home directory, and not just config files. Here's how it works:
Our 6.8 GB agent compresses down to roughly 1–2 GB for daily snapshots. Only what changed between snapshots is stored — so a daily backup after the initial snapshot is often just 50–200 MB of deltas.
When you restore, you get back everything: the Hermes runtime, all Python packages, model weights, cron schedules, system config, apt state, and your agent's custom skills. The agent boots and works immediately — no reinstallation, no rebuilding.
Our snapshot compression brings the 6.8 GB down to about 4.2 GB on disk. With 7 daily snapshots retaining the full machine state, you're looking at ~6–10 GB total — negligible for any modern VPS provider.
Every derez.ai agent instance comes with automatic full-disk snapshots — not home-directory backups, not config exports, but full filesystem snapshots.
Real talk: Most agent hosting services back up your config and call it a day. They don't tell you that restoring won't work because the runtime is missing. We built full-disk snapshots into derez.ai from day one because "it works after restore" is the only standard that matters.
The 69% problem isn't a theoretical edge case — it's what happens to every agent that runs real workloads. Every skill, every integration, every model download pushes more state outside the home directory.
If your agent hosting service backs up only /home or /root, test this: delete a major runtime dependency (say, /usr/local/lib/python3.11), then restore from their backup. If the agent doesn't work, you're paying for a false sense of security, not actual backup.
At derez.ai, your agent's full disk gets backed up every day. No gaps, no missing runtimes, no surprises on restore.
Deploy a Hermes agent with automatic full-disk backups. Use code blog950 for your first month free.
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