Vizioncore states that "to take advantage of the VI3 improvements, all of your existing virtual machines must be migrated from ESX Server 2.X to the new platform. Depending on how many virtual machines you are running, scheduling migrations and cutovers can become complicated, and downtime can become substantial. However, with proper procedures, you can upgrade smoothly so your company can more quickly take adva Vizioncore states that “to take advantage of the VI3 improvements, all of your existing virtual machines must be migrated from ESX Server 2.X to the new platform. Depending on how many virtual machines you are running, scheduling migrations and cutovers can become complicated, and downtime can become substantial. However, with proper procedures, you can upgrade smoothly so your company can more quickly take advantage of the new features. VMware outlines two main methods of performing migrations. The first, “in-place” migrations, involves selecting a particular ESX Server host (and all associated virtual machines) and isolating it for an entire upgrade at once. The second, “migration upgrades,” involves selecting individual virtual machines and migrating them to a new LUN or piece of hardware upon which the VMFS and datastores have already been upgraded. In both cases, the migration methods offered by VMware may be supplemented with third-party software to automate migrations and fast-track infrastructures to enterprise functionality for virtualized environments.” By following these ten steps, companies undertaking VI3 migrations can make sure the process proceeds as smoothly and quickly to ensure fast time-to-business value: Read all documentation thoroughly before you begin: VMware documentation identifies the needed steps, offers specific recommendations, and outlines the expected downtime of any given step. Reading through this documentation is a critical first step in understanding all the variables for migrations in your virtual environments. Identify each virtual machine and its associated host for migration: Create an inventory of your virtual machines and catalog them in one central document. This step ensures you do not miss any virtual machines in the upgrade process. Map interdependencies of virtual machines: Building a map of dependencies among virtual machines is an essential step to flagging their importance in order to minimize downtime of the most critical virtual machines. Create a schedule and workflow of virtual machines in required order: Generally speaking, it is a good practice to perform migrations based on the service level associated with individual machines or groups of virtual machines. Identify the method of migration: Whether you pursue an in-place migration or a migration-upgrade strategy depends on the complexity of your virtual environment and the service levels of your applications. Back-up your existing virtual machines and establish a fail-back strategy: The most important step in a migration procedure is to begin with a back-up of your existing infrastructure. If anything fails during the migration, you will have no virtual machines to restore unless you perform this critical step. Always begin with a test virtual machine: Testing virtual machine migrations is a highly recommended step in order to uncover any issues that you may have that the documentation does not address. Perform migration steps in sequential order: There are four key steps in the migration process that must be performed in sequential order. Failure to follow this order can cause problems. These steps are: 1) install VirtualCenter 2.0, 2) upgrade the VMFS, datastores and hosts, 3) migrate virtual machines, and 4) install VMware Tools in each guest. Manage your downtime window effectively: The amount of downtime you can expect is based on the size of the virtual machine and its interdependencies. It is important to ensure that you employ an acceptable maintenance window during which the application will not be available. Leverage automation whenever possible: You need to choose tools that match the requirements of your environment. For example, esxMigrator from Vizioncore can migrate virtual machines to dissimilar hardware, can fail back to ESX Server 2.X if needed, automatically upgrades VMware Tools, and retains network identity and connections of virtual machines, among other key features. esxMigrator does not require a SAN or VirtualCenter to perform migrations and is easy to use by any level of administrator. It is a good move to drill down into the functionality of automated migration tools before upgrading your environment to ensure you have the right tools for the job. To obtain Vizioncore’s free whitepaper titled “Best Practices for Migrations to VMware Infrastructure 3“, visit Vizioncore’s Web site. Software Development