How to use iSCSI Targets on Citrix XenServer



The business-level Synology NAS servers are Citrix certified, which means by using the iSCSI Target Service, a Synology NAS seamlessly acts as dedicated storage server to provide iSCSI Target storage for your Citrix environment, which will be seen virtually as a local hard drive for as many clients as need be; only they are all stored in a centralized Synology server. Advanced management functions such as Thin Provisioning, iSCSI LUN Backup, MC/S (Multiple Connections per Session) and MPIO (Multiple Path I/O) are available on Synology NAS to strengthen the usability and stability of a network storage environment.

This article will guide you through the process of setting up iSCSI target connection from Citrix XenServer server to your Synology NAS.

What is iSCSI?
iSCSI is an Internet Protocol based storage networking standard for linking data storage facilities. By carrying SCSI commands over IP networks, iSCSI can facilitate data transfers over local area networks (LANs), wide area networks (WANs), or the Internet. Through iSCSI, the space on storage server will be regarded as local disks by client's operation system. But in reality, all data transferred to the disk are actually transferred over network to the storage server.

What is iSCSI Target and LUN?
In SCSI terminology, A LUN (logical unit number) represents an individually addressable (logical) SCSI device that is part of a physical SCSI device (called "Target"). An iSCSI environment emulates the connection to a SCSI hard disk. An iSCSI Target is like a connection interface, and LUNs are essentially numbered disk drives. When an iSCSI Target is connected by an iSCSI initiator (a client), all the LUNs mapped to the iSCSI Target are virtually attached to the client's operation system. Therefore, Initiators can establish and manage file systems on iSCSI LUNs, as they would a raw SCSI or IDE hard drive.


  1. Before You Start
  2. Setting up an iSCSI target on XenServer

1. Before You Start

This article assumes you have performed the following tasks:

  • Hardware installation for Synology DiskStation.
  • Create iSCSI LUNs and Targets on your Synology NAS.

Refer to Quick Installation Guide for more information about hardware and software installation. You can also see Synology DiskStation User's Guide (available at Synology's Download Center) for a general idea about topics related to this article.

2. Setting up and iSCSI Target on XenServer

This section will guide you through the process of adding an iSCSI target on Citrix XenServer:

  1. Launch XenCenter and find the XenServer that will be using an iSCSI Target on the Synology DiskStation and click New Storage:
  2. Nas
  3. Select Software iSCSI and click Next.
  4. Nas
  5. Provide a name for this new Storage Repository and click Next.
  6. Nas
  7. Set the Target Host and discover IQN and LUN in Synology iSCSI storage:
    • Set the IP address of the DiskStation which is hosting the iSCSI Target.
    • Click Discover IQNs.
    • After a Target has been found, click Discover LUNs.
    • After the LUN and Target has been found, click Finish.
  8. Nas
  9. Format the new added disk to the XenServer:
  10. Nas
  11. A new iSCSI Storage Repository is now available on the XenServer for data storage use:
  12. Nas