I am using NFS currently and with the UDP option, i can have the server restart without impacting the clients, it would probably look like a transient network connectivity issue to clients and seems to be handled well, have not seen any issues in a few weeks of testing.
I was unable to find a lot of details on NBD over UDP, could you please let me know if this is supported (for read/write). The objective is to achieve the same functionality of server restart by keeping the server stateless so that if the server has to be restarted, you could still have the clients continue, which does not look like is the case with TCP. Possibly NBD has more reasons than just TCP to support server restart, if so, could you please list a few.
If not UDP, is there an option to restart the NBD server without impacting the clients?