I have an educational client that would like to re-register all agents on all workstations during their summer time PC refresh.

In ZfD 7, they would delete all registered workstations at the beginning of summer. By the time school started, the only registered machines were the ones they re-imaged or newly deployed. They did not (and still do not) leverage any of the asset management features, so a history is not needed. They lost this ability in ZCM 10, but ZCM 11 brought it back. I have not done this in ZCM 11 yet (at least not at this scale), and wonder if any one else has and if any gotchas came up.

The Zone currently has 15,000+ devices registered, but only 12,000 can be resolved with other inventory products. They also have 10,000 new devices that will be deployed this year that will retire 10,000 devices that are over 6 years old. I am concerned that adding 10,000 more registered devices will cause a huge amount of DB swell on top of the already 15,000 registered devices. To prevent the database from growing way to large to hold onto registered devices that will be going away, I want to essentially purge the database and clean all devices out of it. Then as devices with the ZCM 11 agent boot up, my expectation is they will re-register and create a new device object in the zone. It is also expected the registration would happen with out any user intervention.

Will the agents re-register as easy and seamless as they did in ZfD 7?
Is there an easier and faster way to purge devices from ZCM in large scale? (selecting 1000 and choosing to delete seems to take an extremely long time and normally ZCC tends to time out).