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Speaker: Ivan Ischenko, Pre-Sales Engineer, StarWind

StarWind Virtual SAN®
Providing HA storage repositories
for XenServer Pool

Published: September 28, 2018


Traditionally XenServer Pool requires a shared storage to guarantee data safety, allow virtual machines migration, enable continuous application availability and eliminate any single point of failure within an IT environment. XenServer users can choose between two options when selecting the shared storage:

  • Compute and Storage separated solutions that keep compute and storage layers separately from each other, thus making maintenance easier, increasing hardware usage efficiency and allow building the system accurately for solving the task.
  • Hyperconverged solutions that allow sharing same hardware resources for the application (i.e. hypervisor, database) and shared storage, thus decreasing TCO and achieving outstanding performance results.

NOTE: Hyperconverged scenario is not officially supported with Citrix XenServer.

This technical paper is intended for experienced XenServer and Windows system administrators and IT professionals who would like to add StarWind shared storage to XenServer 6.5. It provides users with a step-by step instruction about configuring shared storage in a XenServer environment. This document contains detailed description of creating StarWind HA devices and explains the way of setting up XenServer Pool and XenServer nodes. The document particularly focuses on the process of configuring an iSCSI initiator and connecting and mounting created datastores.

A full set of up-to-date technical documentation can always be found here, or by pressing the Help button in the StarWind Management Console.

For any technical inquiries please visit our online community, Frequently Asked Questions page, or use the support form to contact our technical support department.

Solutions Diagram

The network diagram below illustrates the configuration of the system to perform the actions listed in the document.

the configuration of the system to perform the actions listed in the document.

This document assumes having at least 2 physical servers with XenServer and XenCenter installed. It also assumes having 2 physical servers with StarWind Virtual SAN installed and configured having 2 replicated and synchronized virtual storage devices.

Preparing StarWind Nodes

Preparing the Servers

Install Windows Server 2016 (or 2012 R2) and StarWind VSAN on each host. Detailed StarWind Virtual SAN installation process can be found here:

Make sure that server hardware used for the StarWind Virtual SAN deployment satisfies the requirements listed below.

Minimum requirements:

RAM: 4 GB (plus the RAM cache size if applicable);
CPUs: 1 socket with 2 GHz;
Hard disk 1: 100 GB for OS (recommended);
Hard disk 2: Depends on the storage volume to be used as a shared storage.

Network adapter 1: Management
Network adapter 2: iSCSI1
Network adapter 3: iSCSI2
Network adapter 4: Sync1
Network adapter 5: Sync2

NOTE: It is recommended to set jumbo frames to 9000 for iSCSI and Synchronization traffic.

NOTE: StarWind host allows adding Active Directory Domain Services role if necessary, thus it can serve as a domain controller.

Create HA devices

1.Open Add Device (advanced) Wizard.

2. Select Hard Disk Device as the type of device to be created. Click Next to continue.

3. Select Virtual Disk. Click Next to continue.

4. Specify a virtual disk location and size.

5. Select Thick provisioned disk type.

6. Define a caching policy and specify a cache size (in MB). Also, the maximum available cache size can be specified by selecting the appropriate checkbox.
Optionally, define the L2 caching policy and cache size. Click Next to continue.

7. Specify Target Parameters. Select the Target Name checkbox to enter a custom target name.

8. Otherwise, the name is generated automatically in accordance with the specified target alias. Click Next to continue.

9. Click Create to add a new device and attach it to the target.

10. Click Close to finish the device creation.

11. Right-click the recently created device and select Replication Manager from the shortcut menu.

12. Select Add Replica.

13. Select Synchronous “Two-Way” replication as a replication mode. Click Next to proceed.

14. Specify a partner Host name or IP address and Port Number.

15. Select Failover Strategy.

NOTE: With the Heartbeat failover strategy, one node remains active, even in case of failure of all partner nodes.

With the Node Majority failover strategy, failure of only one node can be tolerated. If two nodes fail, the third one will become unavailable to clients’ requests.

This document describes the creation of an HA device with the Heartbeat failover strategy.

The creation of an HA device with the Node Majority failover strategy is covered in the following document:

16. Select Create new Partner Device and click Next.

17. Select a partner device Location.

18. Click Change Network Settings.

19. Specify the interfaces for Synchronization and Heartbeat Channels. Click OK and then click Next.

20. In Select Partner Device Initialization Mode, select Synchronize from existing Device and click Next.

21. Click Create Replica. Click Finish to close the wizard.

The successfully added device appears in StarWind Management Console.

22. Follow the similar procedure for the creation of other virtual disks that will be used as storage repositories.

Configuring XenServer Hosts

Creating a Pool

To create a pool:

23. Launch XenCenter.

24. Click New Pool. The Create New Pool window appears.

25. Specify the name and description of the pool and click Add New Server.

In the Add New Server window specify the first XenServer host to be added to the pool as well as User name and Password.

26. Click Add.

27. Take the previous steps to add the second XenServer host to the pool.

28. Specify the Master host.

29. Click Create Pool.

30. After creating the pool, the XenCenter window should look as shown in the screenshot below.

Configuring Network Settings

NOTE: Switch the XenServer host to Maintenance Mode for network configuration: right-click the XenServer and select Enter Maintenance Mode from the shortcut menu.

To configure dedicated iSCSI networks:

31. Select the first XenServer host. Switch to the Networking tab.

32. Click Configure.

33. In the appearing window click Add IP address to add networks.

34. In IP address and DNS server settings, configure IP address.

35. Click OK.

36. The window should look as shown in the screenshot below.

37. Exit the Maintenance mode.

38. Select the second XenServer host. Switch to the Networking tab.

39. Repeat the same steps on all XenServer hosts.

40. The window should look as shown in the screenshot below.

Configuring iSCSI Initiator

NOTE: switch XenServer host to the maintenance mode for iSCSI configuration.

Perform the following actions on each XenServer host in the pool:

41. Edit /etc/iscsi/initiatorname.iscsi and set the appropriate iqn for XenServer iSCSI initiator.

42. Edit the /etc/iscsi/iscsid.conf file.

Set the following values:

43. Restart the software iSCSI service:

44. Set the iSCSI services to start automatically when launching XenServer:

Applying Multipathing

NOTE: Switch XenServer host to maintenance mode for multipath configuration.

To apply multipathing take the following actions for each XenServer in the pool:

45. Switch to console tab, edit multipath configuration file running “vi /etc/multipath.conf” command.

46. Insert the following block into the “devices” section:

47. Restart the multipath service:

48. Set the multipath service to start automatically when launching XenServer:

49. Right-click the XenServer and select Properties from the shortcut menu.

50. Click Multipathing Active in the left pane. Select the Enable multipathing on this server checkbox and click OK.

51. Turn off the Maintenance Mode: right-click the XenServer and select Exit Maintenance Mode from the shortcut menu.

52. Reboot the XenServer host.

Adding Shared Storage manually

53. Select the XenServer host. Switch to the Console tab in XenCenter.

54. Run discovery:

55. Connect the targets using their IQNs found by discovery:

56. Perform steps 1-3 for all XenServer hosts in the Pool.

57. Check if the multipath works properly on the first host.


58. Check the multipath on the second host.


59. On Pool Master run the following commands to add SRs:

60. The window should look as shown in the screenshot below.

61. The window should look as shown in the screenshot below.

62. Check the added SRs:

  • First Storage Repository

  • Second Storage Repository


After performing all the steps described in this guide, highly-available shared storage will be accessible to the XenServer hosts. StarWind Virtual SAN will replicate all the data between the hosts and allow XenServer to keep Virtual Machines on the shared storage. Adding StarWind Virtual SAN storage devices into XenServer Pool offers many additional features and benefits such as:

  • synchronous data replication;
  • high availability;
  • automatic failover;
  • snapshots, cloning, migrating and a lot more;

StarWind Virtual SAN is Officially Certified with Citrix XenServer 6.5. Customers can be confident that StarWind Virtual SAN has successfully passed a series of tests established by Citrix. StarWind Virtual SAN effectively work with Citrix XenServer 6.5, provides confidence in joint solution compatibility and a heterogeneous IT infrastructure, combining the power of Citrix XenServer® and StarWind Virtual SAN virtualization, and improving XenServer experience with storage high availability, reliability and protection.