Implementing the remote partition actor

Oct 13, 2025 by pinkandtrash.com 135 views

[NBS] Add Remote Partition Actor to Support Disk Migration Between Different Scale Units

In today's data-driven world, the need for efficient and scalable storage solutions has never been more pressing. The Network Block Device (NBD) is a popular choice for providing block-level access to storage devices over a network. However, as the demand for storage continues to grow, the need for more advanced features such as disk migration between different scale units has become increasingly important. In this article, we will explore the concept of adding a remote partition actor to support disk migration between different scale units, and how it can be achieved using RDMA (Remote Direct Memory Access).

The Network Block Device (NBD) is a protocol that allows a client to access a block device on a server over a network. It is commonly used in cloud computing environments where storage needs to be shared across multiple servers. However, as the size of storage devices continues to grow, the need for more efficient and scalable storage solutions has become increasingly important. One of the key challenges in achieving this is the ability to migrate disks between different scale units.

Currently, the NBD protocol does not support disk migration between different scale units. This is because the protocol is designed to provide block-level access to storage devices on a single server, and does not have the necessary mechanisms to handle data plane requests across multiple servers. As a result, disk migration between different scale units is not possible, and storage administrators are forced to rely on manual processes to achieve this.

To support disk migration between different scale units, a remote partition actor needs to be added to the NBD protocol. This actor will be responsible for handling data plane requests such as write, read, and zero blocks, and forwarding them to the NBS (Network Block Server) on a remote host using RDMA. The remote partition actor will act as a proxy between the client and the NBS, allowing data to be transferred between the two servers without the need for intermediate storage.

RDMA is a technology that allows for direct memory access between two servers over a network. It eliminates the need for intermediate storage and reduces latency, making it an ideal choice for high-performance storage applications. In the context of disk migration, RDMA will be used to transfer data between the client and the NBS on a remote host. This will enable the remote partition actor to forward data plane requests to the NBS, allowing for seamless disk migration between different scale units.

The addition of a remote partition actor to the NBD protocol will bring several benefits to storage administrators. These include:

Improved scalability: With the ability to migrate disks between different scale units, storage administrators will be able to scale their storage infrastructure more easily, without the need for manual processes.
Increased efficiency: The use of RDMA will reduce latency and eliminate the need for intermediate storage, making disk migration faster and more efficient.
Enhanced flexibility: The remote partition actor will provide a flexible and scalable solution for disk migration, allowing storage administrators to migrate disks between different scale units as needed.

The implementation of the remote partition actor will involve several key components. These include:

Remote partition actor: This will be the core component of the solution, responsible for handling data plane requests and forwarding them to the NBS on a remote host using RDMA.
RDMA library: This will be used to implement the RDMA functionality, allowing for direct memory access between the client and the NBS.
NBS: This will be the server-side component of the solution, responsible for providing block-level access to storage devices over a network.

In conclusion, the addition of a remote partition actor to the NBD protocol will provide a scalable and efficient solution for disk migration between different scale units. The use of RDMA will eliminate the need for intermediate storage and reduce latency, making disk migration faster and more efficient. With the benefits of improved scalability, increased efficiency, and enhanced flexibility, the remote partition actor will be a valuable addition to the NBD protocol.

Future work will focus on implementing the remote partition actor and testing its functionality. This will involve:

Implementing the remote partition actor: This will involve writing the code for the remote partition actor, including the logic for handling data plane requests and forwarding them to the NBS on a remote host using RDMA.
Testing the solution: This will involve testing the remote partition actor and verifying its functionality, including its ability to handle data plane requests and forward them to the NBS on a remote host using RDMA.

[1] Network Block Device (NBD) Protocol Specification
[2] RDMA (Remote Direct Memory Access) Protocol Specification
[3] Network Block Server (NBS) Protocol Specification

A. Remote Partition Actor Code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rdma/rdma_cma.h>
#include <rdma/rdma_cm.h>

// Remote partition actor structure
struct remote_partition_actor {
    struct rdma_cm_id *cm_id;
    struct rdma_conn_param conn_param;
    struct ibv_pd *pd;
    struct ibv_mr *mr;
};

// Remote partition actor initialization function
int remote_partition_actor_init(struct remote_partition_actor *rpa) {
    // Initialize RDMA connection parameters
    rpa->conn_param.responder_depth = 1;
    rpa->conn_param.rnr_retry_count = 7;
    rpa->conn_param.max_rd_atomic = 1;
    rpa->conn_param.max_wr = 1;
    rpa->conn_param.max_sge = 1;

    // Create RDMA connection
    if (rdma_create_id(rpa->cm_id, rpa->conn_param, NULL, NULL) != 0) {
        printf("Error creating RDMA connection\n");
        return -1;
    }

    // Create RDMA PD
    if (ibv_create_pd(rpa->cm_id, rpa->pd, NULL) != 0) {
        printf("Error creating RDMA PD\n");
        return -1;
    }

    // Create RDMA MR
    if (ibv_reg_mr(rpa->pd, NULL, 0, IBV_ACCESS_LOCAL_WRITE) != 0) {
        printf("Error creating RDMA MR\n");
        return -1;
    }

    return 0;
}

// Remote partition actor cleanup function
void remote_partition_actor_cleanup(struct remote_partition_actor *rpa) {
    // Close RDMA connection
    if (rdma_destroy_id(rpa->cm_id) != 0) {
        printf("Error destroying RDMA connection\n");
    }

    // Free RDMA PD
    if (ibv_destroy_pd(rpa->pd) != 0) {
        printf("Error destroying RDMA PD\n");
    }

    // Free RDMA MR
    if (ibv_dereg_mr(rpa->mr) != 0) {
        printf("Error deregistering RDMA MR\n");
    }
}

B. RDMA Library Code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rdma/rdma_cma.h>
#include <rdma/rdma_cm.h>

// RDMA library structure
struct rdma_lib {
    struct rdma_cm_id *cm_id;
    struct rdma_conn_param conn_param;
    struct ibv_pd *pd;
    struct ibv_mr *mr;
};

// RDMA library initialization function
int rdma_lib_init(struct rdma_lib *rplib) {
    // Initialize RDMA connection parameters
    rplib->conn_param.responder_depth = 1;
    rplib->conn_param.rnr_retry_count = 7;
    rplib->conn_param.max_rd_atomic = 1;
    rplib->conn_param.max_wr = 1;
    rplib->conn_param.max_sge = 1;

    // Create RDMA connection
    if (rdma_create_id(rplib->cm_id, rplib->conn_param, NULL, NULL) != 0) {
        printf("Error creating RDMA connection\n");
        return -1;
    }

    // Create RDMA PD
    if (ibv_create_pd(rplib->cm_id, rplib->pd, NULL) != 0) {
        printf("Error creating RDMA PD\n");
        return -1;
    }

    // Create RDMA MR
    if (ibv_reg_mr(rplib->pd, NULL, 0, IBV_ACCESS_LOCAL_WRITE) != 0) {
        printf("Error creating RDMA MR\n");
        return -1;
    }

    return 0;
}

// RDMA library cleanup function
void rdma_lib_cleanup(struct rdma_lib *rplib) {
    // Close RDMA connection
    if (rdma_destroy_id(rplib->cm_id) != 0) {
        printf("Error destroying RDMA connection\n");
    }

    // Free RDMA PD
    if (ibv_destroy_pd(rplib->pd) != 0) {
        printf("Error destroying RDMA PD\n");
    }

    // Free RDMA MR
    if (ibv_dereg_mr(rplib->mr) != 0) {
        printf("Error deregistering RDMA MR\n");
    }
}

C. Network Block Server (NBS) Code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rdma/rdma_cma.h>
#include <<br/>
**[NBS] Add Remote Partition Actor to Support Disk Migration Between Different Scale Units: Q&A**

**Introduction**
===============

In our previous article, we explored the concept of adding a remote partition actor to support disk migration between different scale units. In this article, we will answer some of the most frequently asked questions about this topic.

**Q: What is the remote partition actor?**
=====================================

A: The remote partition actor is a new component that will be added to the Network Block Device (NBD) protocol. Its primary function is to handle data plane requests such as write, read, and zero blocks, and forward them to the Network Block Server (NBS) on a remote host using RDMA (Remote Direct Memory Access).

**Q: Why is the remote partition actor necessary?**
=============================================

A: The remote partition actor is necessary because the current NBD protocol does not support disk migration between different scale units. This is because the protocol is designed to provide block-level access to storage devices on a single server, and does not have the necessary mechanisms to handle data plane requests across multiple servers.

**Q: How will the remote partition actor improve disk migration?**
=============================================================

A: The remote partition actor will improve disk migration by allowing data to be transferred between the client and the NBS on a remote host using RDMA. This will eliminate the need for intermediate storage and reduce latency, making disk migration faster and more efficient.

**Q: What are the benefits of using RDMA for disk migration?**
=====================================================

A: The benefits of using RDMA for disk migration include:

* **Improved scalability**: RDMA allows for direct memory access between the client and the NBS, eliminating the need for intermediate storage and reducing latency.
* **Increased efficiency**: RDMA reduces the overhead of data transfer, making disk migration faster and more efficient.
* **Enhanced flexibility**: RDMA allows for flexible and scalable disk migration, enabling storage administrators to migrate disks between different scale units as needed.

**Q: How will the remote partition actor be implemented?**
=====================================================

A: The remote partition actor will be implemented as a new component of the NBD protocol. It will be responsible for handling data plane requests and forwarding them to the NBS on a remote host using RDMA.

**Q: What are the technical requirements for implementing the remote partition actor?**
=====================================================================

A: The technical requirements for implementing the remote partition actor include:

* **RDMA library**: The remote partition actor will require an RDMA library to handle data plane requests and forward them to the NBS on a remote host using RDMA.
* **Network Block Server (NBS)**: The remote partition actor will require a Network Block Server (NBS) to provide block-level access to storage devices on a remote host.
* **Remote partition actor code**: The remote partition actor will require code to handle data plane requests and forward them to the NBS on a remote host using RDMA.

**Q: What are the potential challenges of implementing the remote partition actor?**
=====================================================================

A: The potential challenges of implementing the remote partition actor include:

* **Complexity**: The remote partition actor will require complex code to handle data plane requests and forward them to the NBS on a remote host using RDMA.
* **Scalability**: The remote partition actor will require scalable solutions to handle large amounts of data and high-performance storage applications.
* **Interoperability**: The remote partition actor will require interoperability with existing storage systems and protocols.

**Q: What are the next steps for implementing the remote partition actor?**
=====================================================================

A: The next steps for implementing the remote partition actor include:

* **Implementing the remote partition actor code**: The remote partition actor code will need to be implemented to handle data plane requests and forward them to the NBS on a remote host using RDMA.
* **Testing the remote partition actor**: The remote partition actor will need to be tested to ensure that it is functioning correctly and efficiently.
* **Deploying the remote partition actor**: The remote partition actor will need to be deployed in a production environment to provide disk migration between different scale units.

**Conclusion**
==========

In conclusion, the remote partition actor is a new component that will be added to the Network Block Device (NBD) protocol to support disk migration between different scale units. It will use RDMA to handle data plane requests and forward them to the Network Block Server (NBS) on a remote host. The remote partition actor will improve disk migration by eliminating the need for intermediate storage and reducing latency. The technical requirements for implementing the remote partition actor include an RDMA library, a Network Block Server (NBS), and remote partition actor code. The potential challenges of implementing the remote partition actor include complexity, scalability, and interoperability. The next steps for implementing the remote partition actor include implementing the remote partition actor code, testing the remote partition actor, and deploying the remote partition actor in a production environment.

**References**
==========

* [1] Network Block Device (NBD) Protocol Specification
* [2] RDMA (Remote Direct Memory Access) Protocol Specification
* [3] Network Block Server (NBS) Protocol Specification

**Appendix**
==========

A. **Remote Partition Actor Code**

```c
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rdma/rdma_cma.h>
#include <rdma/rdma_cm.h>

// Remote partition actor structure
struct remote_partition_actor {
    struct rdma_cm_id *cm_id;
    struct rdma_conn_param conn_param;
    struct ibv_pd *pd;
    struct ibv_mr *mr;
};

// Remote partition actor initialization function
int remote_partition_actor_init(struct remote_partition_actor *rpa) {
    // Initialize RDMA connection parameters
    rpa->conn_param.responder_depth = 1;
    rpa->conn_param.rnr_retry_count = 7;
    rpa->conn_param.max_rd_atomic = 1;
    rpa->conn_param.max_wr = 1;
    rpa->conn_param.max_sge = 1;

    // Create RDMA connection
    if (rdma_create_id(rpa->cm_id, rpa->conn_param, NULL, NULL) != 0) {
        printf("Error creating RDMA connection\n");
        return -1;
    }

    // Create RDMA PD
    if (ibv_create_pd(rpa->cm_id, rpa->pd, NULL) != 0) {
        printf("Error creating RDMA PD\n");
        return -1;
    }

    // Create RDMA MR
    if (ibv_reg_mr(rpa->pd, NULL, 0, IBV_ACCESS_LOCAL_WRITE) != 0) {
        printf("Error creating RDMA MR\n");
        return -1;
    }

    return 0;
}

// Remote partition actor cleanup function
void remote_partition_actor_cleanup(struct remote_partition_actor *rpa) {
    // Close RDMA connection
    if (rdma_destroy_id(rpa->cm_id) != 0) {
        printf("Error destroying RDMA connection\n");
    }

    // Free RDMA PD
    if (ibv_destroy_pd(rpa->pd) != 0) {
        printf("Error destroying RDMA PD\n");
    }

    // Free RDMA MR
    if (ibv_dereg_mr(rpa->mr) != 0) {
        printf("Error deregistering RDMA MR\n");
    }
}

B. RDMA Library Code

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <rdma/rdma_cma.h>
#include <rdma/rdma_cm.h>

// RDMA library structure
struct rdma_lib {
    struct rdma_cm_id *cm_id;
    struct rdma_conn_param conn_param;
    struct ibv_pd *pd;
    struct ibv_mr *mr;
};

// RDMA library initialization function
int rdma_lib_init(struct rdma_lib *rplib) {
    // Initialize RDMA connection parameters
    rplib->conn_param.responder_depth = 1;
    rplib->conn_param.rnr_retry_count = 7;
    rplib->conn_param.max_rd_atomic = 1;
    rplib->conn_param.max_wr = 1;
    rplib->conn_param.max_sge = 1;

    // Create RDMA connection
    if (rdma_create_id(rplib->cm_id, rplib->conn_param, NULL, NULL) != 0) {
        printf("Error creating RDMA connection\n");
        return -1;
    }

    // Create RDMA PD
    if (ibv_create_pd(rplib->cm_id, rplib->pd, NULL) != 0) {
        printf("Error creating RDMA PD\n");
        return -1;
    }

    // Create RDMA MR
    if (ibv_reg_mr(rplib->pd, NULL, 0, IBV_ACCESS_LOCAL_WRITE) != 0) {
        printf("Error creating RDMA MR\n");
        return -1;
    }

    return 0;
}

// RDMA library cleanup function
void rdma_lib_cleanup(struct rdma_lib *rplib) {
    // Close RDMA connection
    if (rdma_destroy_id(rplib->cm_id) != 0) {
        printf("Error destroying RDMA connection\n");
    }

    // Free RDMA PD
    if (ibv_destroy_pd(rplib->pd) != 0) {
        printf("Error destroying RDMA PD\n");
    }

    // Free RDMA MR
    if (ibv_dereg_mr(rplib->mr) != 0) {
        printf("Error deregistering RDMA MR\n");
    }
}

C. Network Block Server (NBS) Code