Esxi, makes total sense. There has been a lot of recent issues.
Do you have it closed off to the Internet so the only way would be internal network (like you said the data center)?
Have you considered migrating to qemu/kvm?
You running MS SQL on Windows or Linux?
Yes, hence the reason for suspecting a side attack.
Yes, but no thanks. HiveSQL is an infrastructure, not just one host. In that case, it is not only the hypervisor software that matters but also all the related components, including the sysops skills and knowledge. This extends to the disaster recovery plan as a whole.