Best posts made by arc1

Hi,
I have a question about migration of VMs.
If i put host into maintenance mode, VMs on that host are migrated one by one and it takes quite a bit of time to migrate all of them.
But if i do a manual migration, I can choose multiple (or all VMs) and when i click "migrate" all VMs start migration at the same time. That process is much faster than one by one migration.
Is there any particular reason for not migrating all VMs together on maintenance mode?