IT in the Trades: How a 50-Employee SMB Runs Proxmox and TrueNAS in Production

Trade businesses are one of the most honest customer groups in the SMB world. Work gets done, numbers get calculated, people improvise on the construction site — and the invoices go out in the evening. IT either works, or it stays out of the way. What a trade business with 30 to 80 employees rarely needs: a data centre. What they almost always need: an environment where project drawings, quote calculations and the DATEV bookkeeping run quietly for three years, even when the master tiler pulls up a floor plan from the office at half past nine on a Tuesday night.

This article is an anonymised vertical reference: a concrete but disguised real-world case of a trade business with roughly 50 employees including mobile site managers. The company, the trade and some details are changed — the architecture and the decisions are real. If you have read our best practice for a 3-person law firm, you will recognise the same approach: stay open, do not get naive, and size the hardware so the next five years do not get expensive again.

Starting point: a trade business before modernisation

The business is a mid-sized interior-fit-out trade with its own workshop, three construction crews, a planning office and a commercial department. The 50 employees break down roughly like this:

• 6 people in administration (accounting, payroll, procurement, management)
• 4 people in planning (CAD, measuring, tenders, costing)
• 3 site managers (80 percent on construction sites, with a company tablet and smartphone)
• 2 masters in the workshop
• 35 fitters and helpers (who barely touch a PC but show up in IT through time tracking and photos)

Before the modernisation, IT ran on a single Hyper-V host with local disks, an old Synology NAS as a file server, a Windows share for project drawings, and a DATEV installation that spoke to the tax advisor over an unstable VPN. Backups ran “somehow”. The quote calculation lived in a Lexware install that “had always run” on one specific PC. When that PC died in January, no quotes went out for two and a half days.

The trigger for the modernisation was therefore not a strategic project but a pain point. In SMB trade IT, that is the normal case, and we treat it that way: we do not build the ideal world, we build the next load-bearing step.

Target architecture: why Proxmox and TrueNAS

The target architecture rests on three pillars:

1. Compute — two Proxmox hosts in a cluster, carrying all Windows and Linux VMs.
2. Storage — a TrueNAS system as the central file server for plans, photos, scans and project folders.
3. Backup — a second Proxmox Backup Server at a secondary site plus offsite replication.

Why Proxmox and TrueNAS for a trade business rather than Microsoft Hyper-V plus a Dell SAN? Three reasons:

• Licence cost. A 50-person business quickly pays a five-figure yearly bill for Windows Server licences, SQL Server and Hyper-V management tools. Proxmox with an Enterprise subscription is significantly cheaper, with comparable functionality at this scale.
• Updates and lifecycle. Proxmox hosts stay stable for years, can be kept in production without vendor pressure, and are not tied to an appliance. That fits the trades, where nobody wants to re-tender a server stack every three years.
• Transparency. ZFS snapshots on TrueNAS, PBS backups, Proxmox replication — every piece is auditable, documentable and repairable. No black box.

For hardware we use TrueNAS Enterprise from our partner iXsystems. The current recommendations are M30 and M40, with a Mini R often being enough for smaller operations. If you need a fitting configuration, the TrueNAS configurator is the right starting point — the older M50 and M60 series is EOL and is no longer our recommendation for new projects.

The server room: two Proxmox hosts, one TrueNAS, two UPS units

In an old workshop office there is a small, climate-controlled server room. Half a rack, a 10 GbE switch, two UPS units and the patch panel. Nothing more. That has to be enough, because a real data centre room is economically unrealistic for a 50-person trade business — and it is not needed either.

The components in detail:

• 2x Proxmox host (Intel Xeon Silver, 128 GB RAM, local NVMe for boot and fast storage, 10 GbE NIC) in a cluster. All production VMs sit on the TrueNAS, a few smaller VMs replicate via ZFS to the respective second host.
• 1x TrueNAS Enterprise M-series (M30 class, current hardware) with two pools: an NVMe pool for VM datasets and an HDD pool with two NVMe drives as a metadata vdev for project data.
• PBS instance on separate hardware at a secondary site (workshop annex with its own fibre link).
• Two UPS units controlled via NUT, so a long power failure results in a coordinated shutdown.
• OPNsense as the firewall on a separate appliance, including the VPN concentrator for the site managers.

The operating system on the TrueNAS is 25.10 “Goldeye” — the current stable release we run production systems on. TrueNAS 27 GA is scheduled for early December 2026 and will become our standard after sufficient hands-on time on an internal test system.

Project drawings and construction plans: the most common pain point

For a trade business, the project drawings and construction plans are the heart of the operation. Every active job has a project folder with CAD files, PDFs, construction photos, bills of material, quote calculations, meeting notes and a delivery-note archive. These folders grow to 2 to 20 GB per project — much more for the larger ones.

The TrueNAS carries this data in its own pool. The dataset layout is deliberately flat:

• projects/active — all running projects, SMB share, permissions via Active Directory groups
• projects/archive — finished projects, read-only, older snapshots kept longer
• planning/cad — central CAD library, templates, standard parts
• commercial/dms — document management backend (an ecoDMS VM uses this dataset)
• scans — scanner target folder for the multifunction printer

Snapshot policy on projects/active:

• hourly for 48 hours
• daily for 30 days
• weekly for 12 weeks
• monthly for 36 months

That sounds like a lot but costs surprisingly little disk space thanks to ZFS deduplication and compression. We described the mechanics in more detail in our article on the backup test day with a 30-minute restore.

DATEV, Lexware and the commercial world

DATEV and Lexware environments are still the norm in trade businesses. Both run as VMs on the Proxmox cluster. What we deliberately avoid: we do not migrate the commercial world against the will of the bookkeeping team into the cloud. The lady who has run payroll for 20 years has good reasons for her working environment looking the way it does — and we respect that.

In detail:

• DATEV VM as a Windows Server, with the DATEV software stack and a connection to the tax advisor via the official DATEV data-service interface. Backups of the DATEV database go into PBS.
• Lexware VM with a central database, several clients access it via Terminal Server. The old “Lexware on one PC” setup is gone.
• Quote-calculation VM with the trade-specific software. This VM has a higher snapshot frequency because quotes are especially painful to lose during editing.

PBS backs up all three VMs on a two-hour cycle and replicates to an offsite target on every working day. We covered this topic in depth in our backup strategy for SMB with Proxmox and TrueNAS.

Mobile site managers: tablets, photos and VPN

The three site managers are the most demanding user group — not professionally, but technically. They mostly work outside the company network, upload construction-site photos, pull drawings onto their tablet and occasionally have to adjust quotes while on the road.

We go for a simple, un-fashionable setup:

• WireGuard VPN on OPNsense, clients on iPad and company laptop.
• Access to the TrueNAS via SMB share over VPN. Deliberately no cloud mirror, no OneDrive sync, no “sort-of Dropbox”. The site manager sees the exact same folder structure as the project manager in the office.
• Site photos flow via a small app into the projects/active/<project-no>/photos dataset. That dataset has a snapshot policy that protects photos accidentally deleted in the last 14 days.

What we do not do: we do not turn the construction-site workflow into a cloud cult. If the site has no mobile signal, the site manager has the current plans offline on the tablet — and that is fine.

Monitoring, updates and the honest part

Monitoring runs on a small Zabbix install in its own VM. What we watch:

• SMART values and ZFS pool health on the TrueNAS
• Free space per dataset
• Proxmox cluster status, live-migration readiness, backup jobs on PBS
• OPNsense throughput, VPN sessions
• UPS state and server-room temperature

Patch cycles are fixed. Proxmox hosts get patches in the monthly maintenance window, TrueNAS moves to Enterprise release versions after a staging phase. We deliberately do not chase every minor version. More on that in our description of the TrueNAS support offering.

The honest part: in the first year after the migration there were three bigger events. A failed hard drive, caught by ZFS without data loss. A wrong click that deleted a project folder, recovered from a snapshot in ten minutes. And a DATEV database error after a Windows update, restored from a PBS snapshot within an hour. None of these would have been handled this quietly before the migration.

What this reference case is not

Because we hear this in every first conversation: this reference case is not a data-centre project. There is no cross-site high availability, no stretched cluster, no 99.99 percent SLA. For a 50-person trade business, that would be economically wrong.

What it is: an honest, robust SMB IT environment that carries daily operations on two hosts, one TrueNAS and a solid backup concept. Hardware prices move around, so we do not quote fixed euro amounts here — a load-bearing proposal is available via the DATAZONE IT service or directly through our office.

FAQ on IT for trade businesses

Is Proxmox worth it for a trade business under 50 employees?

Yes, usually from 15 to 20 employees upwards. The deciding factor is less the headcount and more the number of central applications — DATEV, Lexware, DMS, CAD license server, time tracking. As soon as more than three central services come together, a Proxmox cluster carries its weight and is cheaper over time than Microsoft Server licenses or pure cloud setups.

Is a TrueNAS Mini enough for a 50-employee trade business?

For file workloads only, often yes — especially when the VMs sit on separate local storage on the Proxmox hosts. As soon as the TrueNAS also serves VM storage via NFS or iSCSI and real data volumes grow per project, we recommend a TrueNAS M30 or M40. The Mini R series fits micro businesses, small branch sites or replication targets better.

How do you handle DATEV and Lexware — cloud or on-prem?

We migrate both into VMs on Proxmox and let the bookkeeping team work in their familiar interface. The DATEV connection to the tax advisor uses the official DATEV services, not improvised VPN constructs. Cloud replacements for DATEV are possible, but not a project we force onto the business.

How do you protect project drawings and construction plans against ransomware?

Three layers: ZFS snapshots on the TrueNAS for short-term mistakes, Proxmox Backup Server for full VM snapshots, and offsite replication to a second site. Part of the snapshots is additionally anchored as an immutable backup so that even an admin account cannot delete everything.

What happens if the server room burns down?

In this specific case we have a second site on the workshop grounds with its own fibre link, where the secondary PBS and a small TrueNAS for the file portion live. Within hours critical VMs can start there and project data is reachable. For larger businesses or a higher protection level we add offsite replication into a data centre or a cloud backup target.

From which business size does an own Proxmox cluster make sense, and when is managed hosting enough?

From about 10 to 15 employees with multiple business applications an own cluster usually makes economic sense. Below that, managed hosting or a small single host can be the better fit. The relevant factors are not just headcount but availability expectations, data volume and how many business processes hang on a specific application. An honest first conversation with the DATAZONE IT service clarifies this faster than any product sheet.