Case study · Cloud migration
An entire server infrastructure moved to the cloud – in stages
A medium-sized company with around 100 workstations ran all of its business-critical IT in its own server room. INFONET did not simply move the environment; it redistributed it: suitable services to Microsoft 365, everything else to servers in a data centre.
Scope
What had to be moved
Starting point
One server room that everything depended on
Email, user management, company data, accounting, terminal servers and the phone system all depended on the local server infrastructure. The environment had grown over many years and consisted of several specialised systems: a file server with around 2 TB, an Exchange Server with around 150 mailboxes and 1.2 TB of data, Active Directory for around 100 users, terminal servers, an accounting server, a phone system server and a proxy server – plus a backup infrastructure with around 64 TB of capacity.
Maintenance effort grew accordingly: hardware, storage, backup, Exchange, operating systems and business applications all had to be maintained, updated and backed up regularly. On top of that came the risks of a largely local infrastructure – a hardware fault, or a power or air-conditioning problem on site, could hit several core services at once.
And with this architecture, working from home and on the move could only be supported with extra effort. The goal was therefore not to replace the existing servers but to modernise the setup fundamentally.
The approach
Redistribute, don’t just relocate
The obvious route would have been to put all the servers, unchanged, into a different data centre. That would have emptied the server room and changed little else – the same systems, the same maintenance, just somewhere else.
Instead, every service was assessed on what it actually needs. Microsoft 365 handles communication and collaboration. The remaining business-critical server systems, which still require a conventional Windows Server environment, run in an environment built and managed by INFONET in a Hetzner data centre.
The migration was carried out step by step so that day-to-day business was disrupted as little as possible.
Before and after
Where each service runs today
The most demanding part
150 mailboxes and 1.2 TB to Exchange Online
A mailbox migration is nine-tenths preparation. The project included:
- Preparing and cleaning up the existing Exchange environment
- Migrating the mailboxes in stages
- Microsoft 365 integration and user mapping
- DNS changeover including MX and Autodiscover
- SPF, DKIM and DMARC – without them, mail ends up in spam
- Outlook connection on the workstations
- Mobile devices set up again
- Multi-factor authentication for sign-in
Backup
64 TB was never the goal – it was the result of years of growth
The previous backup infrastructure had around 64 TB of storage capacity. Transferring that volume unchanged to the cloud would have created ongoing costs for a size nobody could justify any more.
Production data, retention periods, server backups and cloud data were therefore considered separately. The new concept backs up the remaining server systems, keeps the backups separate from the production systems and monitors the backup processes regularly.
As a result, the backup infrastructure became much easier to oversee – and it now fits the data that actually exists rather than its history.
Security
What was modernised along the way
- Encrypted site connection to the data centre
- New firewall rule set
- Secured administrative access
- Protected terminal server access
- Multi-factor authentication
- Microsoft 365 security configuration
- Separation of production and backup systems
- Patch and update concept with monitoring
Result
A server room became a hybrid environment
Before: on-premises Exchange, a file server, terminal servers, an accounting server, a phone server, a proxy server and a large backup server – all in-house. Today: Microsoft 365 with Exchange Online and OneDrive, server systems in the data centre, a redesigned backup and a secured site connection.
After the migration, INFONET continues to look after the environment: server monitoring, Microsoft 365 administration, user management, Exchange Online, backup checks, patch management, firewall and VPN, terminal servers, Active Directory, troubleshooting and user support. Cloud services, data centre and support therefore all come from a single provider.
- Far less server hardware on the premises
- No more locally run Exchange Server
- Less dependence on the office location and better mobile working
- Professional data centre operation instead of an in-house server room
- Improved backup strategy, sized to fit
- Less maintenance work and better scalability
Project data at a glance
approx. 100 users · 150 mailboxes · 1.2 TB of email data · 2 TB of company data · 64 TB of existing backup infrastructure · Exchange Online migration · OneDrive integration · server migration to the data centre · terminal servers · accounting · phone system · backup · firewall and VPN · ongoing managed service
Frequently asked questions
What prospective clients usually ask
How long does the business stand still during a migration like this?
Ideally, not at all. That is why the migration is done step by step: first preparation and clean-up, then the mailboxes in stages, then the switch of the DNS records. We schedule larger cutovers in maintenance windows – evenings or weekends – and always with a fallback plan in case something does not go as expected.
Does everything really have to go to the cloud?
No – and that is exactly the point of this case study. For email and personal files, Microsoft 365 is clearly the better choice. Business applications with strict latency requirements, large databases or CAD data are often better off staying on a server. Most SMEs end up with a mixed solution.
Why a data centre rather than a server on your own premises?
Because a server room needs power, cooling, access control and spare parts – and because otherwise a fault at the company site hits several core services at once. If you can solve these points properly in-house, you can stay there too; it is a question of cost, not of belief.
What happens to the existing licences and hardware?
That belongs in the planning, not in the clean-up afterwards. Beforehand, we record what is in place, which licences continue, which expire and which hardware can still be put to other use. What is actually left over depends on the individual case.
A note on confidentiality
For reasons of confidentiality, we only publish client names and contact persons with their explicit consent. If you have a specific interest, we are happy to put you in touch personally after consulting the reference client.
Free initial consultation
Are you facing a server replacement?
The point at which the old hardware would need replacing is the right moment to rethink the architecture. We review your environment and show you which services make sense to move to the cloud – and which are better left where they are.
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