[WookieRushing]

Why do you think its easy?

There's a lot of systems where you can easily take down some hosts, but taking down more than N% at a time causes issues. If your fleet is large enough then you are limited by the largest set of hosts where you can only take N% down at a time. Now you could say keep the sets of hosts small or N% large. But that can cause other issues as you typically lose efficiency or zonal outage protection.

A solution to this could be VM live migration or something similar. This breaks down for storage systems where you can't just migrate those disks virtually since they're physical disks or places that don't use VMs.