When transferring IT infrastructure to the cloud, applications, services and data can be transferred partially, service by service, or completely. Therefore, partial and complete migration is distinguished.

Partial migration

Partial migration is usually chosen by large companies with a large number of services and extensive infrastructure. First, non-critical services are transferred (most often these are test environments and user virtual machines), and after them everything else.

Full migration

Full migration is a transfer of the entire infrastructure in a few days. This method usually chooses a small and medium business, the IT structure of which is quite simple.

Migration of physical servers to virtual

Physical servers can be turned into virtual ones using various specialized tools:

Linux dd commands

Clonezilla program, which is loaded from CD or USB;

disk2vhd on Windows

VMware Converter Standalone or StarWind V2V Converter software

specialized commercial products.

Migration from one hypervisor to another

You can use VMware vCenter Converter Standalone to convert a virtual machine from Hyper-V format to VMware format, but it can be used when there is a communication channel between the hypervisor in the cloud and the convertible virtual machine. If there is no such channel, you can use the PowerShell HypervOVAConverter script.

To migrate a virtual machine from VMware Workstation, VMware Fusion, or from an existing virtual infrastructure based on VMware vShere or ESXi, you can use the function to export the virtual machine to an OVF file. OVF (Open Virtualization Format) is a standard for storing and distributing virtual machines. And the OVA format is a tar archive of the catalog with the OVF package.

Before exporting, you must make sure that the virtual machine is not encrypted and turned off. When migrating from Proxmox, you can use the quemu-img utility to obtain a disk image in VMDK format. The same utility will help when switching from KVM or Xen hypervisors.

If the running service cannot be stopped, you can use online migration. Many cloud-portable applications have their own replication facilities. For example, database servers have excellent replication. It is also relatively easy to migrate the Microsoft Exchange mail server, but its transfer has its own characteristics. The transfer of Exchange to the cloud is as follows:

new instance is installed in the cloud.
nodes are carried;
shared folders are transferred (if any)
connectors are switched;
the old server is deleted.

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