What is a Virtual SAN?
A virtual storage area network (SAN) is a software-based component that provides a virtualized ‘pool’ of storage to multiple virtual machines (VMs) and applications. In order to achieve this, data is passed (shared) between servers over a network using a protocol such as iSCSI or fibre channel.
Traditional IT infrastructure models that require shared storage use a physical SAN, NAS (network-attached storage) or a dedicated storage array which are specialist pieces of hardware requiring dedicated network infrastructure. By implementing a virtual SAN, an organization is able to reduce the amount of physical hardware needed to run the storage element of their solution. All that’s required are two or more x86 servers, a hypervisor, and a software-defined storage layer.
Different vendors refer to virtual storage area networks in various ways (i.e. virtual SAN, vSAN, VSAN), and their exact definition of the solution differs - for instance in the network protocols used. Wikipedia refers to the term ‘VSAN’ only as a fibre channel concept, for example.
How Does a Virtual SAN Work?
The theory behind a virtual SAN is based on hyperconvergence, a term used to describe the consolidation of computing, networking, and storage resources, into a single, streamlined datacenter architecture. Similarly, a virtual SAN enables organizations to eliminate the dedicated storage hardware and associated networking within their physical infrastructure. Instead, the virtual SAN is installed on commodity x86 servers, often (but not always) the same servers that generally handle the organization’s compute functionality.
A virtual SAN converges traditional datacenter hardware components into a single virtualized appliance, controlled by a software layer. It can either be installed as a software program that runs on a virtual machine (VM), or be incorporated into a storage vendor's firmware and sold as a single, consolidated solution.
The software component of a virtual SAN is sometimes known as a VSA (virtual storage appliance). A VSA is installed on each server within a virtual SAN cluster, above the hypervisor layer. So a virtual SAN will typically have two or more VSAs running, communicating with each other to provide the shared storage necessary.
There are different deployment options when it comes to virtual SANs; the storage and compute don’t always have to be located on the same hardware. For example, a storage-only server SAN deployment enables storage to be deployed on just a couple of nodes in a cluster, that only handle the storage. The cluster then shares that storage out over the network, to compute-only nodes. Those nodes don’t have to have the virtual SAN installed directly on them, but can still access the storage. This type of separation of compute and storage resources is more typical of traditional IT architectures, with the difference that a virtual SAN typically enables the organization to use much more common and inexpensive standard x86 servers instead of the dedicated hardware required for NAS and SAN appliances.
What Are the Benefits of Virtual SANs?
Physical storage infrastructure, such as a NAS or SAN, typically requires specialist hardware and more significant network architecture that can tolerate high bandwidth and low latency. These components can be expensive, and the costs add up significantly for organizations with multiple locations, each requiring storage infrastructure. A virtual SAN on the other hand, generally only needs commodity x86 servers and far less networking equipment, all of which makes it much more affordable. Virtual SAN solutions also decrease CAPEX and OPEX costs, as they are less expensive to purchase up front, and require less resources to upkeep (i.e. specialist IT support, cooling, spare parts, physical space).
There are some virtual SANs out on the market today that are capable of enabling shared storage across two or three server nodes. By duplicating data and applications across multiple servers, these solutions eliminate single points of failure, which enables high availability within IT infrastructures. This differs from a physical SAN appliance, which as a single piece of infrastructure, represents a single point of failure within an organization’s IT architecture. A reliance on a single piece of hardware for something critical such as data storage poses a risk to the day-to-day activities of a business. Any downtime can be crippling to an organization’s operations, and therefore eliminating single points of failure should be a priority.
Best practices for ensuring high availability in an IT infrastructure are available in this white paper.
As a physical piece of hardware, a physical SAN must be installed in a very specific way within the datacenter, and has several strict requirements in terms of management and maintenance. A virtual SAN has lower requirements and enables an organization to tailor their configuration to meet their exact needs, and deploy it in a way that best suits them. It can be configured in many different ways, and provides businesses with much more flexibility to select the components (hardware and software) that make the most sense for their environment.
Discover more about the benefits of switching from traditional, physical storage infrastructure to a virtual SAN, particularly in regard to costs, in our blog post: Looking to Reduce Your IT Budget? Consider Switching to a Virtual SAN
Virtual SANs and Edge Computing
Organizations with edge computing environments face unique challenges, and require IT solutions that are designed to meet their specific needs. They are often working with restricted budgets, as they have to deploy their solutions across many sites, have limited resources (i.e. floor space, IT staff, networking capacity), and can be located in remote places that aren’t easily accessible by IT maintenance personnel.
A virtual SAN is an ideal storage solution for organizations at the edge. As mentioned above, virtual SANs are cost-effective, which is essential for organizations that often have multiple sites to manage and can’t afford to deploy expensive physical hardware at each location. They are also more compact and lightweight, decreasing CAPEX and OPEX costs, which can add up quickly for organizations with hundreds or thousands of sites.
Virtual SANs are easier to maintain and manage, and can create a highly available shared storage environment, which is ideal for edge organizations positioned in remote locations that are difficult to access. In the event that a server goes down, a virtual SAN ensures systems stay up and running while the organization waits for an IT specialist to come out and address the problem. This is essential for edge locations that can’t afford to lose productivity and revenue, due to system downtime.
Retail stores, manufacturing plants, and branch offices are all examples of edge environments that can benefit from transitioning from a physical SAN or NAS, to a virtual SAN. These types of sites may not be ideally suited for bulky IT hardware, which require specialist care and optimal conditions (i.e. floor space, temperature, cleanliness) to operate. The requirements to install and manage a virtual SAN are minimal, and they enable edge organizations to be much more flexible when it comes to deploying infrastructure that fits within their environment, not the other way around.
Check out our Beginners Guide to Edge Computing for additional information about the unique requirements of edge environments, how edge computing works, and the benefits of edge computing solutions.
StorMagic SvSAN: A Virtual SAN
StorMagic SvSAN is a virtual SAN solution that enables simple, cost-effective, flexible virtualized storage. It turns the underlying storage of any x86 server into highly available shared storage, within clusters of two or three servers (nodes). SvSAN is based on software-defined storage that eliminates the need for physical SANs, and is ideal for edge environments.
Some of the benefits offered by StorMagic SvSAN include: