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StarWind Virtual SAN®
Providing HA storage repositories for XenServer 7.x

Published: September 26, 2018

Introduction

Traditionally XenServer Pool requires 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 the same hardware resources for the application (i.e. hypervisor, database) and shared storage, thus decreasing TCO and achieving outstanding performance results.

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 7.x (up to 7.5). It provides users with a step-by step instruction on how to configure shared storage in a XenServer environment. The document particularly focuses on the process of configuring an iSCSI initiator and connecting and mounting created datastores.

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

A full set of up-to-date technical documentation can always be found here, or by pressing the Help button in StarWind Management Console. Also, you can invoke Technical Support directly from StarWind VSAN Help.

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 that there are at least 2 physical servers with XenServer and XenCenter installed. It also assumes that there are 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. The detailed StarWind Virtual SAN installation process can be found here:

https://www.starwindsoftware.com/resource-library/starwind-virtual-san-quick-start-guide-installation

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

Minimum requirements:

RAM: 4 GB (plus the size of the RAM cache 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 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.

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

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

9. Click Close to finish the device creation.

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

11. Select the Add Replica button.

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

13. Specify a partner hostname, IP address and port number.

14. 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 client’s requests.

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

https://www.starwindsoftware.com/resource-library/creating-highly-available-device-using-node-majority-failover-strategy

15. Select Create New Partner Device and click Next.

16. Select the Partner Device location.

17. Click Change Network Settings.

18. Specify the interfaces for Synchronization and Heartbeat channels. Click OK. Then click Next.

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

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

21. The successfully added device appears in StarWind Management Console. Follow the similar procedure for creation of other virtual disks that will be used as storage repositories.

Configuring XenServer Hosts

Creating a Pool

22. Launch XenCenter.

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

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

25. In the Add New Server window specify the first XenServer host to be added to the pool as well as Username and Password. Click Add.

26. Take the steps described above to add the second XenServer host to the pool.

27. Specify the Master host.

28. Click Create Pool.

29. 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:

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

31. Click Configure.

32. In the appeared window, click Add IP Address to add networks.

33. Configure the IP address.

34. Click OK.

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

36. Exit the Maintenance mode.

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

38. Repeat the same steps on all XenServer hosts.

39. The window should look as shown on the screenshot below.

Configuring iSCSI Initiator

NOTE: XenServer host must be in the maintenance mode for iSCSI configuration.

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

40. Can be done through XenCenter Interface. Edit /etc/iscsi/initiatorname.iscsi and set appropriate iqn for XenServer iSCSI initiator.

41. Edit the /etc/iscsi/iscsid.conf file using built-in text redactors such as vi or nano.

Set the following values:

42. Restart the software iSCSI service:

43. Set the iscsi services to start automatically while launching XenServer:

Applying Multipathing

NOTE: XenServer host must be in the maintenance mode for multipath configuration.

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

44. Switch to the Console tab, edit multipath configuration file running the “nano /etc/multipath.conf” command.

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

46. Restart the multipath service:

47. Set the multipath service to start automatically while launching XenServer:

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

49. Click Multipathing in the left pane. Select the Enable multipathing on this server checkbox. Click OK.

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

51. Reboot the XenServer host.

52. Perform the same steps for the second 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 the steps 1-3 for all XenServer hosts in the Pool.

57. On Pool Master, run the following commands to add SR:

58. Check if the multipath is working properly with the multipath -ll command on the first host.

59. Check the multipath on the second host.

C:\Users\sw-qa-7\Pictures\x2-multipath-new.png

60. Check the added SR:

Conclusion

After performing all the steps described in this guide, XenServer Pool with StarWind Virtual SAN® storage devices as a shared storage will be created. It is a perfect shared storage solution used for keeping XenServer Virtual Machines. 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 for Citrix XenServer 7.x (up to 7.5) as a dedicated iSCSI storage in Compute and Storage separated scenario. Customers can be confident that StarWind Virtual SANTM has successfully passed a series of tests established by Citrix. Therefore, they can be trusted to work effectively with Citrix XenServer 7.x (up to 7.5), providing confidence in joint solution compatibility and a heterogeneous IT infrastructure, combining the power of Citrix XenServer® virtualization and StarWind Virtual SAN® storage virtualization, and improving XenServer experience with storage high availability, reliability and protection.