At my previous employer we've run it just fine from an EC2 instance talking to a MySQL RDS database. At some point the triggers from pt-osc were really hurting

At my previous employer we've run it just fine from an EC2 instance talking to a MySQL RDS database. At some point the triggers from pt-osc were really hurting when trying to migrate big (several billion rows) table with heavy traffic and gh-ost really helped with that. That said, gh-ost is definitely a big boy tool and it took us a few tries to get the settings just right. No downtime or anything, we just had to delete the new table and start over. Still annoying when it wastes several hours :)