Home > All, Citrix, NetScaler > How does #Citrix #NetScaler SDX isolate its instances?

How does #Citrix #NetScaler SDX isolate its instances?

Ok, I received this question the other day and this article is really spot on! Get a cup of coffee and enjoy! 😉

And remember this: YOU CAN ONLY HAVE 7 INSTANCES/1Gbps NIC!!!! So if you intend to host more than 7 VPX’s on your SDX then ensure that you plan your network design if you use 1Gbps otherwise go for the 10Gbps ports and SPFS.

NetScaler SDX Appliance with SR-IOV and Intel-VTd

This article contains information about the Single Root I/O Virtualization (SR-IOV) and Intel Virtualization Technology for Directed I/O (Intel-VTd) technology and how NetScaler appliance uses this technology to achieve fully isolated high performance NetScaler instances.

NetScaler SDX Appliance with SR-IOV and Intel-VTd

Server Virtualization presents both a tremendous opportunity and a major challenge for Enterprise Data Centers and Cloud Computing infrastructure. Current Hypervisors already facilitate the consolidation of many servers that are not utilized efficiently to a smaller number of physical servers delivering better space utilization, lower power consumption, and reduced overhead costs.

Virtualization architectures are built on a virtualization layer called a Virtual Machine Monitor or Domain 0 that becomes the primary interface between a virtual machine and the physical hardware. Even though virtualization allows multiple virtual machines to share the same hardware, it also creates additional overhead and can lower server performance as it becomes the bottleneck between a virtual machine and input/output (I/O) hardware as the number of virtual machines increase.

The NetScaler SDX appliance breaks through these performance bottlenecks by leveraging next generation of I/O virtualization technology called SR-IOV as defined by the PCI-Special Interest Group (SIG). SR-IOV enabled Intel chips along with Intel VT-d enable the NetScaler SDX appliance to significantly reduce virtualized network processing overheads, and provide more secure and predictable mechanisms for sharing I/O device among multiple virtual machines.

Intel Implementation of Single Root I/O Virtualization

Intel has worked with the PCI-SIG to define the SR-IOV specification. As shown in the following image, SR-IOV provides dedicated I/O to virtual machines bypassing the software virtual switch in the Virtual Machine Manager (VMM) completely, and Intel Ethernet Controllers improve data isolation among virtual machines. Another feature of SR-IOV is a feature called Virtual Functions. These are Lightweight PCIe functions that allow a single physical port to look like multiple ports. Therefore, multiple virtual machines can now have direct assignment on the same port. This increases the scalability of the number of virtual machines on the machine through more efficient I/O device sharing.

Intel VT-d Technology

Intel VT-d is a hardware enhancement for I/O virtualization that is implemented as part of core logic chipset. Intel VT-d defines an architecture for DMA remapping that improves system reliability, enhances security and…

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