Memory system including memory module, memory module, and operating method of memory module

A memory system includes a nonvolatile memory module and a first controller configured to control the nonvolatile memory module. The nonvolatile memory module includes a volatile memory device, a nonvolatile memory device, and a second controller configured to control the volatile memory device and the nonvolatile memory device. The first controller may be configured to transmit a read request to the second controller. When, during a read operation according to the read request, normal data is not received from the nonvolatile memory device, the first controller may perform one or more retransmits of the read request to the second controller without a limitation on a number of times that the first controller performs the one or more retransmits of the read request.