Loss of a Tang server
The loss of an individual Tang server within a load balanced set of servers with identical key material is completely transparent to the clients.
The temporary failure of all Tang servers associated with the same URL, that is, the entire load balanced set, can be considered the same as the loss of a network segment. Existing clients have the ability to decrypt their disk partitions so long as another preconfigured Tang server is available. New clients cannot enroll until at least one of these servers comes back online.
You can mitigate the physical loss of a Tang server by either reinstalling the server or restoring the server from backups. Ensure that the backup and restore processes of the key material is adequately protected from unauthorized access.