Reading Time: 8 minutes

StarWind Software is a US privately held company (headquartered in Wakefield, Massachusetts, USA) which began in Feb 2009 as a spin-off from Rocket Division Software (founded in 2003), with its StarWind iSCSI Target solution as main product. After that, the company has grown and also the products have evolveld following the market trends and customer needs.

Now their most interesting product is StarWind Virtual SAN: a scale-out and “shared-nothing” storage solution that works also with 2 nodes, configuration that can be really important for remote office and branch office (ROBO) or SMB cases.

StarWind Virtual SAN is entirely software-based (it runs on a Windows Server Operating System), that can be used both as a dedicated storage solution (for example as a scale-out fileserver) or can run on hypervisor (it support both VMware vSphere and Microsoft Hyper-V as also Xen and KVM) as a VSA (or as a service in case Hyper-V is used) in order to build an hyper-converged storage solution:

This second case is quite interesting considering that only few solutions can start from a 2-node cluster configuration, and for this reason it can be consider also a good alternative to the dismissed VMware VSA.

Most important it creates a fully fault-tolerant and high-availability storage pool without the need of shared storage, SAS JBOD or any external storage. It simple use local storage and mirror the data across the different nodes. It’s completely up to the system administrator decide how many replicas of a particular VM or LUN are kept alive and how many active storage controllers a cluster should use. Individual disks, memory modules, whole compute and storage hosts can fail but uptime is never compromised.

Virtual SAN provisions and manages storage with VM workload in mind: Virtual SAN uses StarWind Log-Structured File System (LSFS) and sophisticated multi-level caching technique in order to avoid as much of a random I/O dominating VM world as possible but still without deploying extremely expensive and cost-inefficient all-flash model. It can use PCIe flash, NVMe, SSD, SAS drives and also SATA drives (all block level storage supported by Windows Server can be used).

So the most common user cases of this product is build a storage (dedicated or hyper-converged, but the second one can be the most interesting) for a virtualization platform:

  • Shared storage for Microsoft Hyper-V VMs (with iSCSI or SMB3 front-end protocol)
  • Shared storage for VMware vSphere or free ESXi VMs (with iSCSI front-end protocol)
  • Shared storage for Citrix XenServer or other Xen/KMM VMs (with iSCSI or NFS front-end protocol)

Certified hypervisors include VMware ESXi 5.5 and 6.0 (see VMware HCL), Hyper-V on Windows Server 2012 R2 (or Hyper-V Server 2012 R2), Citrix XenServer 6.5 (see Citrix HCL).

But it can also be used as a dedicated storage for Exchange, SQL Server, … or also a simple failover file server for common data, VDI profiles, backups and other general purpose usage (both with SMB3 and NFS front-end protocols). In this general purpose case probably the most interesting configuation is the “shared-nothing” scale-out file server that give you now the benefit of Microsoft Storage Spaces Direct without waiting for Windows Server 2016 (and without the high requirements in term of network cards and networking bandwidth).

Hardware (or virtual hardware for the virtual storage appliance case) system requirements are the following:

  • CPU: Intel Xeon E5620 (or higher), or equivalent AMD Opteron (for VSA you need 4 virtual processors with 2 GHz reserved)
  • RAM: 4GB Minimum
  • Network: at least two 1 GbE NICs (for VSA at least 2 NIC ports dedicated as separate vSwitches)
  • Storage: it is required to have at least 2 GB of disk space for StarWind installation and logging

For the software part, it runs as a set of Windows services so a Windows Server is required:

  • Recommended Operating Systems: Windows Server 2012 R2 (it works on Windows Server 2008 R2, but you will lose the SMB3 capability)
  • Server Core is supported (as also Hyper-V Server), but in this case you cannot use the StarWind Management Console locally

Download is super easy: just one single (very small) file! Installation and configuration are also easy and well described in the product guides or in this blog post: StarWind Virtual SAN: A Storage Solution for your virtual environment. Note that you manage StarWind Virtual SAN also from System Center VMM using SMI-S (see this post).

As written one of the most interesting configuration is the hyper-converged storage: on VMware (and Xen or KVM) it works as a VSA running on the hypervisor itself and can simple start from two node and grown with more (in a scale-out model).

In order to provide HA and resiliency you need both an heartbeat (for cluster monitoring) and a sync (for data replication) networks. Note that for the two nodes configuration, are used sophisticated algorithms to compensate for the requirement of the third node (the “voting” or “witness” nodes for quorum configuration) to avoid split-brain scenario.

For a two nodes cluster are supported also the cross cables (at least two different connections to provide network resiliency).

To configure an high availability storage solution (with 2 or more nodes), each virtual disk must be replicated (with a synchronous replication) to another node. This can be managed really simple from the StarWind Management Console if you are managing all the nodes from the same console. You have to create a virtual disk and then use Replication Manager to add a synchronous “two-way” replication and specify a node partner:

StarWind-VirtualSAN-HAAs you can notice, StarWind Virtual SAN support also asynchronous replication, designed for site disaster recovery scenario, in this case the replica is “one-way” and usually on a remote system.

Device creation is quite easy and you can make a new one with a single window using the wizard, but you can also choose the advanced option and specify more settings. Supported devices are hard disk, tape devices (it support a Virtual Tape Library (VTL)) or optical disk devices:


For hard disk different types are supported: virtual disk (an image file that can be stored on the local filesystem), physical disk (mainly a disk passthoug) or RAM disk:


Virtual disk can be thick or thin provisioned, in the second case you can enable the LSFS in-line deduplication feature. Also note that both legacy 512 physical sector size or the new 4K sector size are supported:


At this point there is one interesting features of version 8: the Server-Side Cache with two level of cache (L2 was introduced in v8). StarWind uses conventional RAM as a write buffer and Level 1 cache to adsorb writes, and can use flash for Level 2 cache.

Finally a really important aspect: there is a free edition of Virtual SAN with a lot of features (see this comparison between the free and the paid editions), than can be used also in production and support HA! It’s limited to one or two nodes (in the second case you can have HA) but is not limited in term of managed space. The biggest limit is than can be used ONLY in a dedicated storage configuration and cannot be (for example) as an hyper-converged storage. This also limit the possibility to test it in a virtual machine (because it’s recognized as an hyper-converged configuration, also if you simple use VMware Workstation), in this case you need a trial key instead of the free one.

To request the free key or the trial key, just use this link.


Virtualization, Cloud and Storage Architect. Tech Field delegate. VMUG IT Co-Founder and board member. VMware VMTN Moderator and vExpert 2010-24. Dell TechCenter Rockstar 2014-15. Microsoft MVP 2014-16. Veeam Vanguard 2015-23. Nutanix NTC 2014-20. Several certifications including: VCDX-DCV, VCP-DCV/DT/Cloud, VCAP-DCA/DCD/CIA/CID/DTA/DTD, MCSA, MCSE, MCITP, CCA, NPP.