Certain users prefer to use Tachyon as a pure caching system. In this case, it should not require to have a persistent layer such as UFS. However, in the current implementation, a UFS is required to run the system.
In order to deploy without a UFS when perform as a caching system, here are two possible solutions:
a. Have a fake UFS implementation which ignores all the commands.
b. In addition to solution (a), separate the data persistency and journalling.