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A '''Virtual Storage Area Network (VSAN)''' is a logical representation of a physical [[Storage Area Network]] (SAN). A VSAN abstracts the storage-related operations from the physical [[storage layer]], and provides shared storage access to the applications and [[virtual machine]]s by combining the servers' local storage over a network into a single or multiple storage pools.
{{refimprove|date=September 2018}}
{{Fibre Channel}}


The use of VSANs allows the isolation of traffic within specific portions of the network. If a problem occurs in one VSAN, that problem can be handled with a minimum of disruption to the rest of the network. VSANs can also be configured separately and independently.
In [[computer networking]], a '''virtual storage area network''' ('''VSAN''') is a collection of [[Port (computer networking)|port]]s from a set of connected [[Fibre Channel switch]]es, that form a virtual [[Fibre Channel fabric|fabric]]. Ports within a single switch can be partitioned into multiple VSANs, despite sharing hardware resources. Conversely, multiple switches can join a number of ports to form a single VSAN.


==Technology==
[[Cisco Systems]] designed VSANs modelled after the [[VLAN|virtual local area network]] (VLAN) concept in [[Ethernet]] networking, but applying the idea to a [[storage area network]]. In October 2004 the Technical Committee T11 of the [[International Committee for Information Technology Standards]] approved VSAN technology as a standard of the [[American National Standards Institute]] (ANSI).


===Operation===
A VSAN, like each Fibre Channel (FC) fabric, can offer different high-level protocols such as [[Fibre Channel Protocol|FCP]], [[Fibre Channel over IP|FCIP]], [[FICON]], [[iSCSI]]. Each VSAN is a separate self-contained fabric using distinctive security policies, zones, events, memberships, and name services. Traffic is also separate.
A VSAN operates as a dedicated piece of software responsible for storage access, and depending on the vendor, can run as a Virtual Storage Appliance (VSA), a storage controller that runs on a [[virtual machine]] (VM).<ref>{{cite web|url=https://searchservervirtualization.techtarget.com/definition/Virtual-storage-appliance-VSA |title=Virtual storage appliance (VSA) |website=Techtarget |date=November 1, 2012 |access-date=July 8, 2021}}</ref> It is also available as an appliance, such as [[StarWind Software|StarWind]] Virtual SAN, [[DataCore]] SANsymphony, or [[StorMagic]] SvSAN, or as software on the [[hypervisor]] [[kernel]] level such as [[VMware vSAN]].<ref>{{cite web|url=https://www.gartner.com/reviews/market/hyperconverged-infrastructure-software/vendor/datacore-software/product/sansymphony/alternatives |title=Competitors and Alternatives to SANsymphony |website=Gartner |date= |access-date=July 8, 2021}}</ref> A VSAN can be tied to a specific hypervisor, known as hypervisor-dedicated, or it can allow different hypervisors, known as hypervisor-agnostic.<ref name="techtgarget2">{{cite web|url=https://searchvirtualdesktop.techtarget.com/tip/VDI-hypervisor-selection-Does-it-matter-what-you-pick |title=VDI hypervisor selection: Does it matter what you pick? |website=TechTarget|date=June 15, 2012|access-date=July 29, 2021}}</ref>


Different vendors have different requirements for the minimum number of nodes that participate in a resilient VSAN cluster. The minimum requirement is to have at least 2.<ref name="techcoffee">{{cite web|url= https://www.tech-coffee.net/deploy-a-2-node-starwind-vsan-free-for-vmware-esxi-6-5/ |title=Deploy a 2-node StarWind VSAN Free for VMware ESXi 6.5 |website=Tech Coffee |date=April 18, 2017 |access-date=July 9, 2021}}</ref>
Unlike a typical fabric that is resized switch-by-switch, a VSAN can be resized port-by-port.


===Protocols===
The use of VSANs allows the isolation of traffic within specific portions of the network. If a problem occurs in one VSAN, that problem can be handled with a minimum of disruption to the rest of the network. VSANs can also be configured separately and independently.
For sharing storage over a network, VSAN utilizes protocols including [[Fibre Channel]] (FC), [[ISCSI|Internet Small Computer Systems Interface]] (iSCSI), [[Server Message Block]] (SMB), and [[Network File System]] (NFS), as well as proprietary protocols.

===Applications===
A VSAN fills a similar role as physical SAN infrastructure, but is also used for workload virtualization which can include databases, [[Virtual desktop infrastructure]] (VDI) environments, file servers, [[customer relationship management|CRM systems]], and other enterprise applications.<ref name="techtarget1">{{cite web|url=https://searchvmware.techtarget.com/tip/How-VMware-vSAN-differs-from-a-traditional-VSAN |title=VMware vSAN vs. SAN: What are the differences? |website=TechTarget|date=September 10, 2020|access-date=July 29, 2021}}</ref>

A VSAN is a popular solution for remote office/branch office networks. By using commodity x86 server hardware, networks can be configured faster and at lower cost.<ref name="techcoffee"/>

There are also applications with [[DMZ (computing)|DMZ]], an isolated network that sits outside a company's firewall, and areas with space constraints, such as vessels, where a reduced hardware footprint 2-3 node deployment has a better chance of fitting.

By being able to work on top of commodity hardware, a VSAN is often used for building highly available networks across two or more sites that are combined in a single cluster, a type of deployment known as stretched clustering.

A VSAN can also create highly available [[hybrid cloud]] environments by combining existing on-premises resources with public cloud environments.<ref>{{cite web|url= https://searchcloudcomputing.techtarget.com/definition/hybrid-cloud |title=What is hybrid cloud? Everything you need to know |website=Tech Target |date=May 1, 2021 |access-date=July 9, 2021}}</ref>

==Advantages==
The primary advantage of a VSAN is its ability to provide shared storage. It also increases the resiliency of storage systems by allowing the creation of redundant data copies across the servers in a VSAN cluster. It does this while requiring less hardware and power consumption than a physical SAN. Using a VSAN for local storage provides other resiliency options including [[Disk mirroring|mirroring]] or [[Erasure code#Applications of erasure coding in storage systems|erasure coding]] with different parity levels.<ref name="techtarget1"/>

Another advantage is that unlike a typical fabric that is resized switch-by-switch, a VSAN can be resized port-by-port.

==Similar concepts==
A VSAN is often associated with [[Hyper-converged infrastructure|hyperconvergence]], a concept which refers to unifying computing, networking, and storage resources, within a single server. Similarly, a VSAN shifts away from having a separate physical storage layer and required [[networking stack]], and instead combines storage from multiple nodes into a virtualized and consolidated storage layer. VSANs take control of the storage-related operations, access and features allowing the implementation of [[data deduplication]], [[data compression]], high availability and other features, on commodity x86 server hardware. VSAN is also associated with [[software-defined storage]] (SDS).<ref>{{cite web|url=https://www.enterprisestorageforum.com/software/software-defined-storage/ |title=What Is Software Defined Storage? Features & Benefits |website=Enterprise Storage Forum |date=February 22, 2018 |access-date=July 8, 2021}}</ref> However, VSAN can be also used in [[Converged infrastructure|converged architectures]] where VSAN is deployed on dedicated storage nodes as a cluster, and presents the shared storage over a network to compute nodes.


==See also==
==See also==
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{{Reflist}}
{{Reflist}}


[[Category:Computer networks]]
[[Category:Data management]]
[[Category:Telecommunications engineering]]
[[Category:Storage area networks]]
[[Category:Fibre Channel]]
[[Category:Fibre Channel]]

Revision as of 00:08, 30 July 2021

A Virtual Storage Area Network (VSAN) is a logical representation of a physical Storage Area Network (SAN). A VSAN abstracts the storage-related operations from the physical storage layer, and provides shared storage access to the applications and virtual machines by combining the servers' local storage over a network into a single or multiple storage pools.

The use of VSANs allows the isolation of traffic within specific portions of the network. If a problem occurs in one VSAN, that problem can be handled with a minimum of disruption to the rest of the network. VSANs can also be configured separately and independently.

Technology

Operation

A VSAN operates as a dedicated piece of software responsible for storage access, and depending on the vendor, can run as a Virtual Storage Appliance (VSA), a storage controller that runs on a virtual machine (VM).[1] It is also available as an appliance, such as StarWind Virtual SAN, DataCore SANsymphony, or StorMagic SvSAN, or as software on the hypervisor kernel level such as VMware vSAN.[2] A VSAN can be tied to a specific hypervisor, known as hypervisor-dedicated, or it can allow different hypervisors, known as hypervisor-agnostic.[3]

Different vendors have different requirements for the minimum number of nodes that participate in a resilient VSAN cluster. The minimum requirement is to have at least 2.[4]

Protocols

For sharing storage over a network, VSAN utilizes protocols including Fibre Channel (FC), Internet Small Computer Systems Interface (iSCSI), Server Message Block (SMB), and Network File System (NFS), as well as proprietary protocols.

Applications

A VSAN fills a similar role as physical SAN infrastructure, but is also used for workload virtualization which can include databases, Virtual desktop infrastructure (VDI) environments, file servers, CRM systems, and other enterprise applications.[5]

A VSAN is a popular solution for remote office/branch office networks. By using commodity x86 server hardware, networks can be configured faster and at lower cost.[4]

There are also applications with DMZ, an isolated network that sits outside a company's firewall, and areas with space constraints, such as vessels, where a reduced hardware footprint 2-3 node deployment has a better chance of fitting.

By being able to work on top of commodity hardware, a VSAN is often used for building highly available networks across two or more sites that are combined in a single cluster, a type of deployment known as stretched clustering.

A VSAN can also create highly available hybrid cloud environments by combining existing on-premises resources with public cloud environments.[6]

Advantages

The primary advantage of a VSAN is its ability to provide shared storage. It also increases the resiliency of storage systems by allowing the creation of redundant data copies across the servers in a VSAN cluster. It does this while requiring less hardware and power consumption than a physical SAN. Using a VSAN for local storage provides other resiliency options including mirroring or erasure coding with different parity levels.[5]

Another advantage is that unlike a typical fabric that is resized switch-by-switch, a VSAN can be resized port-by-port.

Similar concepts

A VSAN is often associated with hyperconvergence, a concept which refers to unifying computing, networking, and storage resources, within a single server. Similarly, a VSAN shifts away from having a separate physical storage layer and required networking stack, and instead combines storage from multiple nodes into a virtualized and consolidated storage layer. VSANs take control of the storage-related operations, access and features allowing the implementation of data deduplication, data compression, high availability and other features, on commodity x86 server hardware. VSAN is also associated with software-defined storage (SDS).[7] However, VSAN can be also used in converged architectures where VSAN is deployed on dedicated storage nodes as a cluster, and presents the shared storage over a network to compute nodes.

See also

References

  1. ^ "Virtual storage appliance (VSA)". Techtarget. November 1, 2012. Retrieved July 8, 2021.
  2. ^ "Competitors and Alternatives to SANsymphony". Gartner. Retrieved July 8, 2021.
  3. ^ "VDI hypervisor selection: Does it matter what you pick?". TechTarget. June 15, 2012. Retrieved July 29, 2021.
  4. ^ a b "Deploy a 2-node StarWind VSAN Free for VMware ESXi 6.5". Tech Coffee. April 18, 2017. Retrieved July 9, 2021.
  5. ^ a b "VMware vSAN vs. SAN: What are the differences?". TechTarget. September 10, 2020. Retrieved July 29, 2021.
  6. ^ "What is hybrid cloud? Everything you need to know". Tech Target. May 1, 2021. Retrieved July 9, 2021.
  7. ^ "What Is Software Defined Storage? Features & Benefits". Enterprise Storage Forum. February 22, 2018. Retrieved July 8, 2021.