How do I use iSCSI Targets on Windows computers with Multiple Connections per Session (MC/S) support?

How do I use iSCSI Targets on Windows computers with Multiple Connections per Session (MC/S) support?

Purpose

In virtual storage setups, ensuring optimal resource utilization, maximum throughput, minimized response times, and preventing overloads is crucial. Leveraging Multiple Connections per Session (MC/S) for iSCSI connections enhances failover and load balancing capabilities, providing a superior, dependable storage service and outperforming multipath I/O (MPIO) in efficiency.

Synology NAS devices equipped with two or more network interfaces support MC/S for iSCSI Targets, enabling effective failover and load balancing arrangements. This article guides you through the process of using iSCSI Targets on Windows systems that accommodate MC/S.

Environment

Synology NAS

  • SAN Manager:
    • iSCSI LUNs and Targets have been created.
    • Allow multiple sessions from one or more iSCSI initiators has been selected (configurable at SAN Manager > iSCSI > Edit > Advanced).

Resolution

  1. Press Windows key + S and type iSCSI Initiator to launch iSCSI Initiator. Go to the Discovery tab and click Discover Portal… to add every IP address used by your Synology NAS. The IP addresses will appear in Target portals.11.png
  2. Go to the Targets tab, select a Target, and then click Connect.12.png
  3. Select Add this connection to the list of Favorite Targets and click Advanced… to proceed.13.png
  4. Select Default from the Local Adapter drop-down list (if there are multiple options, choose Microsoft iSCSI Initiator). Select an IP address from each of Initiator IP and Target portal IP drop-down lists. These two IP addresses must be in the same subnet.14.png
  5. Select a Target and click Properties to add additional connections.15.png
  6. Click MCS… in the Sessions tab.16.png
  7. Choose an MCS policy, such as Round Robin, and click Add… for another connection.17.png
  8. Click Advanced… in the pop-up window.18.png
  9. Select Default the Local Adapter drop-down list (if there are multiple options, choose Microsoft iSCSI Initiator). Select an IP address from the Initiator IP drop-down list, and then select another IP address other than the one specified in step 4 from the Target portal IP drop-down list. These two IP addresses must be in the same subnet.19.png
  10. On your Synology NAS, go to SAN Manager (or iSCSI Manager before DSM 7.0) to check if the two IP addresses are included in the Service Status.20.png
Purpose
Environment
Resolution
Further reading