Some common source platforms for servers include physical Windows and Linux hosts, that is, operating systems that are installed on bare-metal servers. Some source systems are on other hypervisors, like Microsoft Hyper-V, while some systems already reside in a vSphere environment, but they need to be moved to a separate vSphere environment, perhaps one that is not owned or inherently trusted by the source. The application is an important component as well. Well-known applications that are easy migration candidates include Microsoft Active Directory (AD), SQL Server, or Exchange. All of these existing platforms are common sources for servers when moving to a new vSphere environment.
The method of migration is dependent on the source platform. Some common migration methods are listed as follows, along with their source platforms and associated drawbacks:
- Physical servers, Windows, or Linux:
- vCenter Converter: This method is called a physical-to-virtual conversion, and it was discussed in the previous section. Drawbacks include downtime for the application during cutover. If the system is resource-intensive, downtime for the entire conversion process may be needed, which could take hours. Only some Linux distributions are supported.
- Third-party converter tools like PlateSpin Migrate: These are very similar to vCenter Converter, but are licensed at a cost. The drawbacks are the same as those of vCenter Converter.
- Microsoft applications:
- Often, the best way to migrate a server into a vSphere environment is to use native tools that are built into the system. Active Directory, for example, has a well-understood and well-supported replication engine that makes standing up a new Domain Controller relatively easy. The drawback to migrating with Active Directory replication is the need to add complexity to the AD environment and possible Domain Name System (DNS) changes, which could impact the entire environment.
- SQL Server: There are many ways to migrate an SQL database: backup and restore, mirroring, log shipping, Microsoft Cluster Services (MSCS), and Always-On Availability Groups (AAGs). The drawbacks of migrating with native SQL tools include varying degrees of downtime for the database.
- Exchange: Backup and restore, Database Availability Group (DAG), mailbox move; drawbacks include downtime and the length of time to migrate.
- Microsoft Hyper-V:
- vCenter Converter is a good candidate for migrating VMs on Hyper-V. This is known as a Virtual-to-Virtual (V2V) conversion, and it has the same drawbacks as any other vCenter Converter migration.
- The Zerto virtual replication software is mainly used for disaster recovery, but it's also an excellent migration tool. Downtime is minimal, and the setup is not difficult. The drawbacks include the cost, as it's a licensed product.