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Creating HA LSFS Device with StarWind Virtual SAN

Published: August 7, 2017


This technical paper describes how to create an HA device with StarWind Virtual SAN™. This virtualization software allows achieving high performance and fault tolerance of your storage architecture. It eliminates the need for physical shared storage since StarWind mirrors the internal resources between the servers. Once StarWind iSCSI targets are connected to all cluster nodes, the HA devices are treated as local storage by both hypervisors and clustered applications. Fault tolerance is achieved by providing the multipath access to all storage nodes. Configuring StarWind Virtual SAN simplifies management and operation of your storage infrastructure, as well as boosts performance with no dedicated storage hardware or proprietary equipment required.

This guide is intended for experienced Windows system administrators and IT
professionals who would like to configure the StarWind Virtual SAN solution. This document provides detailed instructions on how to create a minimal 2 node shared storage configuration with high availability using StarWind Virtual SAN that runs on top of Windows Server 2012 R2.

A full set of up-to-date technical documentation can always be found here, or by clicking 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.

Technical description and requirements

An LSFS device is a log-structured file system (journal file system) that keeps track of the changes that are made in a journal. This file system keeps no data, only changes. LSFS is a snapshotbased file system and uses snapshots based on the concept of journaling file system. Every snapshot is incremental and occupies additional space that is equal to the changes made since the previous snapshot creation. Junk rate predetermines the maximum allowed LSFS growth (overprovisioning) comparing to the declared LSFS size. The default rate is 60% causing LSFS filesegments might use 2.5 times more space than the initial LSFS size. Additionally, metadata occupies up to 20% of the initial LSFS size, resulting in a total overprovisioning of LSFS devices at 200%.

LSFS requirements:

1. 4.6 GB of RAM per 1 TB of LSFS size without deduplication. For example, if you have a 10
TB LSFS device, it requires 46 GB of free RAM.

2. 7.6 GB of RAM per 1 TB of LSFS size with deduplication. For example, if you have a 10 TB
LSFS device, it requires 76 GB of free RAM.

3. Over-provisioning is 200% (LSFS files can occupy 3 times more space compared to the
initial LSFS size).

Creating High Availability LSFS Device

1. Launch StarWind Management Console: double-click the StarWind tray icon.

NOTE: StarWind Management Console cannot be installed on a GUI-less OS. You can install it on any of the GUI-enabled Windows Editions including the desktop versions of Windows.

If StarWind Service and Management Console are installed on the same server, the Management Console will automatically add the local StarWind instance to the Console tree after the first launch. Then, the Management Console automatically connects to it using the default credentials. To add remote StarWind servers to the Console, use the Add Server button on the control panel.

2. StarWind Management Console will ask you to specify a default storage pool on the server you’re connecting to for the first time. Please configure the storage pool to use one of the volumes you have prepared earlier. All the devices created through the Add Device wizard will be stored on the configured storage pool. Should you decide to use an alternative storage path for your StarWind virtual disks, please use the Add Device (advanced) menu item.

Press the Yes button to configure the storage pool. Should you require to change the storage pool destination, press Choose path… and point the browser to the necessary disk.

NOTE: Each of the arrays that will be used by StarWind Virtual SAN to store virtual disk images should meet the following requirements:

• initialized as GPT;
• have a single NTFS-formatted partition;
• have a drive letter assigned.

3. Select the StarWind server where you wish to create the device.

4. Press the Add Device (advanced) button on the toolbar.

5. Add Device Wizard will appear. Select Hard Disk Device and click Next.

6. Select a Virtual disk and click Next.

7. Specify the virtual disk name, location, and size. Click Next.

8. Specify virtual disk options.

Choose the LSFS option instead of Thick-provisioned. In case if you need the deduplication on LSFS device, you can check the “Deduplication”. Click the Next button to proceed.

NOTE: StarPack Cache is the low-level cache that is located between the disk and the LSFS log. It caches fragments of the log, which are later prepared for writing to disk or read from the disk. If deduplication is enabled on the device, the data in the StarPack cache is also deduplicated. The recommended size is 16 MB.

NOTE: Use 4096 Virtual Block size for Windows based; 512 for Linux based (ESXi/Xen/KVM)

Click Next

9. Define the caching policy and specify the cache size.

NOTE: It is recommended to put 1 GB of L1 cache in the Write-Back mode per 1 TB storage capacity.

Click Next.

10. Define the Flash Cache Parameters policy and size if necessary. Choose the SSD location in the wizard. Click Next to continue.

NOTE: The recommended size of the L2 cache is 10% of the initial StarWind device size.

11. Specify target parameters.Select the Target Name checkbox to enter a custom name of a target. Otherwise, the name will be generated automatically based on the target alias. Click Next to continue.

12. Click Create to add a new device and attach it to the target. Then, click Close to close the wizard.

13. Right-click the servers field and select Add Server. Add a new StarWind Server which will be used as the second HA node.

Click OK and the Connect button to continue.

14. Right-click the device you have just created and select the Replication Manager.

The Replication Manager window will appear. Press the Add Replica button.

15. Select Synchronous two-way replication.

Click Next to proceed.

16. Specify the partner server IP address.
The default StarWind management port is 3261. If you have configured a different port, please, type it in the Port number field and Click Next.

17.  Select Heartbeat as the Failover Strategy.

18. Choose Create new Partner Device and click Next

19. Specify the partner device location if necessary. You can also modify the target name of the device.

Click Next.

20. On this screen, you can select the synchronization and heartbeat channels for the HA device. You can also modify the ALUA settings.

Click Change Network Settings.

21. Specify the interfaces for synchronization and Heartbeat.

Click OK. Then click Next.

NOTE: It is recommended configuring Heartbeat and iSCSI channels on the same interfaces to
avoid the split-brain issue.

22. Select Synchronize from existing Device as a partner device initialization mode and click Next.

23. Press the Create Replica button and click Close.

24. The added device will appear in StarWind Management Console.

25. Discover and connect created targets in iSCSI initiator which you are using in your environment.


StarWind makes it possible to achieve redundancy and fault tolerance in your storage environment with only 2 nodes available and no additional storage hardware or proprietary equipment necessary. With StarWind Virtual SAN, the HA LSFS configuration significantly improves data availability. Data remains available at a second node should a first node go down because of hardware failure, network congestion or otherwise. Thus, the HA LSFS storage allows avoiding the single point of failure in your virtual infrastructure and restarting the VM on the other host