Remote persistence issue of RDMA read

[xuecheng qi]

Hi all, 

In case the client turns off DDIO and reads data using RDMA read directly from the remote NVM of the server to the local NVM region, does the client need additional operations to ensure persistence?

THanks!

Xuecheng Qi

[Janek Mi]

Hi  Xuecheng Qi

The short answer is: yes. RDMA read data ends its journey in CPU cache because you probably still have DDIO turned ON on the client-side.
To persist the read data you have to call pmem_persist() or its equivalent.