[ps]

Cost.

We recently moved one rack to the different DC in the same city and used Digitalocean droplets to avoid downtime. Services running on Linux were migrated without high-availability (e.g. no pgsql replication, no redis cluster, single elasticsearch node...) and we just turned off Windows VMs completely due to licensing issues and no need to have them running at night.

The price of this setup was almost 4x higher than what we pay for colo. Our servers are usualy <5 years old Supermicro, we run on Openstack and Ceph (S3, rbd) and provide VPNaaS to our clients.

AWS/GCP/Azure was out of question due to cost. We considered moving Windows servers to Azure with the same result - the cost of running Windows Server (AD, Terminal, Tomcat) + MS SQL was many times higher than the price of colo per month. It is bizarre that you can buy the server running those VMs approximately every 3 months for the Azure expenses (Xeon Platinum, 512GB RAM).