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Method and apparatus to connect multiple FC hosts to centralized storage without a FC SAN fabric

IP.com Disclosure Number: IPCOM000240291D
Publication Date: 2015-Jan-21
Document File: 7 page(s) / 66K

Publishing Venue

The IP.com Prior Art Database

Abstract

Storage Area Networks ( SAN ) are increasingly being used to provision storage for Virtual Machines ( VM ) in cloud environments. Typically Fibre Channel ( FC ) or Fibre Channel over Ethernet ( FCoE ) SANs are used to interconnect servers and storage where high performance is desired. A typical small setup consists of one or more hypervisors and a high performance storage controller connected to two redundant SAN Fabrics. With the advent of powerful servers and Virtual Machine technology, a large number of virtual machines can be consolidated on a single hypervisor. Therefore in some setups there can be only one or two physical servers each executing multiple Virtual Machines, and only a single storage controller. In such environments, the cost of dual redundant SAN switches can be significant.

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Method and apparatus to connect multiple FC hosts to centralized storage without a FC SAN fabric

     Storage Area Networks ( SAN ) are increasingly being used to provision storage for Virtual Machines ( VM ) in cloud environments. Typically Fibre Channel ( FC ) or Fibre Channel over Ethernet ( FCoE ) SANs are used to interconnect servers and storage where high performance is desired. A typical small setup consists of one or more hypervisors and a high performance storage controller connected to two redundant SAN Fabrics.

     With the advent of powerful servers and Virtual Machine technology, a large number of virtual machines can be consolidated on a single hypervisor. Therefore in some setups there can be only one or two physical servers each executing multiple Virtual Machines, and only a single storage controller. In such environments, the cost of dual redundant SAN switches can be significant.

Existing Solution :

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     A typical setup consists of a single physical server with one or more Host Bus Adapters (HBA) connected to two independent SAN fabrics. The physical server is running multiple virtual machines on the hypervisor. The FC HBA driver logs into the SAN switch and registers itself with the Fabric Name Server using FLOGI. In response to a FLOGI request, the Fabric Login Server within the switch assigns a 24-bit NPort ID to the HBA.

     High performance Virtual Machine environments allow each Virtual Machine to directly access the devices on the FC SAN using the Raw Device Mapping mode (RDM in VMWare terminology). This enables each virtual machine to access the SAN directly bypassing the hypervisor, thus reducing access latency and improving performance of each Virtual Machine.

     NPort ID Virtualization (NPIV) technology allows a single physical N_Port to establish multiple virtual FC logins & register with the Fabric Name Server as though they were physical FC NPorts. A new NPort ID is assigned for each NPIV login. NPIV logins are created using the FDISC request. This technology is used by the hypervisor to enable each virtual machine to log into the fabric using an FDISC request and get assigned a new NPort ID by the switch. Now the virtual machines look like physical machines on the SAN fabric.

     FC switches implements the Fabric Name Server which enables connected N_Ports to discover other N_Ports on the fabric.

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     This allows the storage administrator to perform LUN mapping, Zoning, QoS assignment and other storage administration functions for each virtual machine. Thus each Virtual Machine gets access to the devices on the SAN directly.

     It must be noted that in the above scenario, the function of the switch is reduced to providing FC Name Service to a single port on the host, thus increasing costs of the deployment. Extending to 16GB or 32GB FC SAN environments where a single HBA port on the host can drive 16GB or 32GB traffic for all the hosted Virtual Machines, the switch becomes more expensive. Instead it...