Build · Cloud Consulting

Cloud migration, with zero downtime

From on-premise to cloud, without disruption. Audit, roadmap and controlled cutover to a robust, resilient infrastructure, with zero service interruption.

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0Service interruption

Lift & refactorDepending on context

Multi-cloudAWS - Azure - GCP - Alibaba

What it covers

Audit of the existing estate and migration roadmap
Lift & shift or refactoring migration
Progressive cutover with no interruption
Post-migration optimization and FinOps

How we work

Understand first

We start from your real estate and constraints, not a theoretical model.

Cut over without disruption

Progressive, reversible, tested migration. Production never stops.

Which path for each application

A cloud migration is not decided as a block. Each application follows its own path, chosen during the audit according to its criticality, coupling and remaining lifetime.

Rehost (lift & shift). The application moves as is onto cloud virtual machines. The fastest way out of a datacenter, optimising afterwards.

Replatform. Few code changes, but the database, storage or runtime move to managed services. Part of the operations work disappears without a rewrite.

Refactor. The application is reworked to use the cloud: containers, serverless, elasticity. Longer, kept for the applications that carry the business and will last.

Retire or retain. Part of the estate is no longer used and is switched off; another part stays on site for a real reason (regulatory constraint, specific hardware) and is connected to the cloud.

To leave a whole datacenter, see our datacenter-to-cloud migration offer. To prepare the project in-house, read our advice for moving from on-premise to the cloud.

Our method, from audit to operations

1. Audit of the existing estate. Inventory of servers, applications, flows and dependencies, criticality of each domain, security and compliance constraints.

2. Priced roadmap. One path per application, migration waves ordered from the least coupled to the most critical, and the target running cost in the cloud.

3. Cloud foundations. Accounts, network, identities, logging and backups set up once, as infrastructure as code, before the first application.

4. Progressive cutover. Data replication, parallel run, verification, then traffic cutover with rollback possible until the last moment.

5. Optimisation and operations. Right-sizing, switching off non-production environments, FinOps, then 24/7 managed services if you want them.

Cost and funding of a cloud migration

The cost of a migration depends on the number of applications and how tightly coupled they are far more than on the size of the infrastructure. The audit prices it path by path, and compares today's running cost with the target cost in the cloud.

A migration does not cut the bill by itself: a like-for-like rehost often costs more than the original datacenter. The savings come from what follows, once sizing is adjusted and managed services replace machines maintained by hand.

Part of the cost can be funded: the AWS MAP programme covers a share of the assessment and of the move out of a datacenter. Access goes through an AWS partner.

Frequently asked questions

How long does a cloud migration take?

It depends on scope: an audit first, then a domain-by-domain path. Our reference: in late 2017 we migrated our own datacenter and moved 100 clients over with zero interruption.

Will there be downtime?

The target is zero downtime: progressive, reversible, tested cutover. Production never stops.

Lift & shift or refactoring?

Both, depending on context. Lift & shift is fast; refactoring exploits managed services. We price both paths in the audit.

Does a cloud migration lower costs?

Not by itself. A like-for-like rehost often costs more than the original datacenter. The savings come after the migration: right-sizing, switching off non-production environments, managed services instead of maintained machines.

Is there funding for a cloud migration?

Yes. Cloud providers run programmes that cover part of the cost of assessment and of moving out of a datacenter, such as AWS MAP. Access goes through a partner. We are an AWS Select partner.

AWS, Azure or GCP: which cloud should you choose?

The one that fits your applications, your in-house skills and your data-location constraints, not a choice of principle. We migrate to AWS, Azure, GCP and Alibaba Cloud, and the audit compares the options on your case.

Where we operate

We operate your platforms worldwide, in every cloud region, with no geographic limit.

MigrationGCP→AWSRefactoringWell-Architected

/ They trust us

Premaccess is driving the modernization of our stack to managed AWS services, domain by domain, without ever blocking production. We move forward on the product, they secure the scale-up.