Closing the MA will result in starting the entire migration process over. Do not close the Migration Assistant at any point during the migration workflow.
During the migration workflow, no changes are made to the source Windows vCenter Server. The option to copy historical and performance data is also available. By default, the configuration and inventory data of the Windows vCenter Server is migrated. The second purpose of the MA is copying the source Windows vCenter Server data. This is a helpful guide of the migration steps that need to be completed. At the bottom of the MA is the Migration Steps, which will be available until the source Windows vCenter Server is shutdown. The MA also displays some information about the source Windows vCenter Server. More information on deployment type considerations prior to a migration can be found here. Keep in mind changing a deployment type is not allowed during the migration workflow. It will also show the source and the destination deployment types.
The Migration Assistant displays warnings of installed extensions and provides a resolution for each.
The first is running pre-checks on the source Windows vCenter Server. The Migration Assistant serves two purposes. The first step of the migration workflow requires running the Migration Assistant (MA). The migration workflow includes upgrading from either a Windows vCenter Server 5.5 or 6.0 to VCSA 6.5. Copying the configuration and inventory of source vCenter Server by default. The Migration Tool does all the heavy lifting. No longer requiring scripts and many long nights of moving hosts one cluster at a time. The new Migration Tool included in the vCenter Server Appliance (VCSA) 6.5 is a game changer. works great! done this for years at several locations.VCenter Server migrations have typically taken massive planning, a lot of effort, and time. I used iDRAC to manage everything on the upgrades and reboots and can do it anywhere with a VPN connections. Then take the last one off maintenance mode after the upgrades, check your HA status and maybe rebalance some of the earlier hosts back to the last host to help out the load balancing. I can usually do 4 hosts in maybe 2 hours if I keep focused and not squirreled on to something else. Don't get distracted and leave some on one version and others on the older.especially if on a HA vmware cluster. Then go through the rest of the hosts in the same manner, rotating out which one is in maintenance mode.
Make sure it's backed up first - FTP is easy to setup - then once it's stable, I run the Dell Lifecycle controller upgrades for all firmware, BIOS, etc on the host and once that's stable (all in maintenance mode) then I will upgrade the host to let's say v6.7 update 2.the same version or lower than the VCSA. When I run upgrades, I run the VCSA first. just don't get it backwards and update your hosts before the vCenter appliance. You might have reasons to keep hosts back a version or so - based on Hardware options.so running VCSA on 6.7 update 2 for example and keeping your hosts on v6.0 is fine. Always keep your VCSA - virtual center appliance at the same level or "ahead" of your hosts.