  Persistence of updates to remote byte-addressable persistent memory (PM),
using RDMA operations (RDMA updates), is a poorly understood subject.
Visibility of RDMA updates on the remote server is not the same as persistence
of those updates. The remote server's configuration has significant
implications on what it means for RDMA updates to be persistent on the remote
server. This leads to significant implications on methods needed to correctly
persist those updates. This paper presents a comprehensive taxonomy of system
configurations and the corresponding methods to ensure correct remote
persistence of RDMA updates. We show that the methods for correct, fast remote
persistence vary dramatically, with corresponding performance trade offs,
between different remote server configurations.
