StorMagic SvSAN – Overview

StorMagic SvSAN is a software-defined storage solution that turns commodity servers into highly available shared storage.

A Virtual Storage Appliance (VSA), that runs on VMware vSphere or Microsoft Hyper-V, is used to manage internal or direct-attached storage providing iSCSI targets.

The iSCSI targets are assigned to hypervisor hosts, formatted with a file system and utilized as shared storage.

The product specially fits the needs of small, medium-sized enterprises and remote branch offices where typically a 2-node cluster has been deployed per site.


SvSAN allocates storage in two different ways:

  • VMDKs, using the free space of a VMFS datastore, a vmdk can be created and assigned to a VSA as storage
  • RDMs, a RAID Lun, created with the underlying storage controller, can be assigned to VSA using a raw device mapping

The product utilizes the following network types:

  • Management, used for accessing the web GUI, plug-in or CLI
  • iSCSI, listens for incoming connection requests from iSCSI initiators
  • Mirror, used by VSA to communicate data and metadata associated with mirrored volumes

A typical vSphere networking scenario, using four network interface cards, can be comprised of three virtual switches.


  • VMkernel – Management network
  • Virtual machine port group – Production virtual machines, SvSAN management


  • VMkernel – vMotion, iSCSI traffic
  • Virtual machine port group – SvSAN iSCSI, mirror traffic


  • VMkernel – vMotion, iSCSI traffic
  • Virtual machine port group – SvSAN iSCSI, mirror traffic

A crossover cable can be used on the vSwitches utilized for iSCSI-mirror traffic to reduce hardware costs and points of failure.


To avoid split-brain situations caused by failures, SvSAN provides a quorum service called Neutral Storage Host (NSH), installed onto a server separate from the VSA, which acts as a tiebreaker and assists in deciding cluster leadership.



SVSAN main features:

  • Virtual San, a software-defined, highly available shared storage
  • Synchronous mirroring, data is written to two VSA ensuring protection against hardware failures
  • High availability (HA), service are monitore and failed over in case of hardware failure
  • Caching, accelerates disk performance by using SSD disks as caching area
  • SvSAN stretched clusters, VSAs can be geographically separated
  • VSA restore, quick recovery of a SvSAN VSA following a hardware failure
  • Centralized monitoring and management, monitor and manage SvSAN VSAs remotely from a single location

For the complete list check the SvSAN Data Sheet.

VSA requirements:

  • 1 vCPU core with at least 2 GHz
  • 1 GB memory (2 GB if caching is used)
  • 2 virtual disks
    • 512 MB boot device for storing configuration data
    • 20 GB device used for meta-data journaling and temporary file storage

StorMagic recommends to set CPU and memory reservation.

Hypervisor support:


VMware vCenter support:


Harware requirements:

SvSAN works with any x86 server that exists on the VMware vSphere ESXi or Microsoft Hyper V Hardware Compatibility List (HCL).

NSH operating system requirements:

  • Microsoft Windows 7 (64-bit)
  • Microsoft Windows 8 (64-bit)
  • Microsoft Windows Server 2008 (64-bit)
  • Microsoft Windows Server 2008 R2 (64-bit)
  • Microsoft Windows Server 2012
  • Microsoft Windows Server 2012 R2
  • Microsoft Hyper-V Server 2012
  • Microsoft Hyper-V Server 2012 R2
  • Linux x86 – Debian 7 (32-bit)
  • Linux x86 – Debian 7 (64-bit)
  • Linux ARM – Raspbian Wheezy3
  • Linux ARM – Raspbian Jessie3

In addition NSH can be installed on to the VMware vCenter Server Appliance (vSphere 5.5 and Higher) or a specialized NSH Appliance can be deployed.

Stay tuned for the next posts in which I will go on with the deployment and configuration of this interesting storage solution.