I/O Virtualization (IOV) is the next wave in data center optimisation. The technology removes the rigid constraints of traditional I/O infrastructure from servers, providing the next critical step to realising the promise of the agile data center. With the help of this innovation, businesses are able to quickly respond to continuously changing market conditions, bandwidth requirements and spikes in data transfer.
IOV enables a more flexible approach to data centre infrastructure. The term “I/O Virtualization” refers to the transparent separation of I/O resources from the compute resources in the data center. At the hardware level, this means the physical removal of I/O resources including host bus adaptors (HBAs) and Network Interface Cards (NICs) from the server. The server chassis therefore houses only the CPU and memory, thus acting as a pure compute engine. The I/O resources from multiple servers are then consolidated and pooled into one single IOV switch which creates a virtual image of each I/O adapter (virtual adapter) that is presented to each server. The IOV switch increases I/O utilisation of the I/O resources to more than 80% by sharing the physical adaptors between multiple servers and enabling all servers to access a single I/O adapter simultaneously. The switches substantially increase the flexibility of the I/O resources by dynamically allocating them to servers on-demand and with no loss of throughput. The physical servers remain unaware that their I/O resources have been physically moved.
There are multiple connectivity standards that can be used to deploy IOV in the data center including Ethernet, InfiniBand and the server native PCI Express® interconnect. Using PCI Express (PCIe) requires no changes to servers because the I/O interconnect is standardised around the PCIe interface found in all server chipset and I/O devices. PCI Express removes the need to deploy any new network in the data center as a single PCIe cable connects directly the IOV switch to each server’s native PCIe bus. The PCIe cable replaces all network and storage cables per server that were required in traditional I/O deployments. The IOV switches also eliminate the network and storage access layer switches from the rack and provide servers with the full connectivity bandwidth into the corporation IT infrastructure. The I/O performance is almost identical as when the I/O adapters are plugged directly into the servers as PCIe doesn’t introduce any extra protocol processing overhead.
For the CIO considering an I/O virtualization implementation, the benefits of the technology including a reduction of more than 60% in I/O capex, energy consumption, server management complexity and opex costs, can be realised immediately. IOV switches manage the entire I/O resources of the connected server as a single entity, enabling servers to be wired once and I/O resources to be dynamically allocated and modified without any physical reconfiguration. These benefits, alongside improved manageability, can account for up to half the acquisition and maintenance costs of servers....
The benefits of I/O virtualization can be extended when deploying fibre Channel over Ethernet (FCoE). I/O Virtualization focuses on maximising the value of the expensive high performance I/O adaptors associated with enterprise servers (be it 10 GbE, FCoE, SAS/SATA RAID, FC or other). FCoE aims to eliminate the FC infrastructure by unifying the storage and networking interconnect into a single 10 G Ethernet fabric. Since FCoE requires 10 G Ethernet (with the CEE extensions in both the NICs and the switches), it is likely to remain an expensive interconnect. The adoption of I/O virtualization in server systems will lower the barrier to adoption for FCoE (and 10 GbE in general) by distributing the cost of one 10 G port over multiple servers.
Because I/O virtualization addresses the cost of all high-performance I/O, it has usage models and benefits which go beyond the domain of FCoE.
For example, by virtualizing SAS/SATA RAID controllers and DAS, I/O virtualization enables disc-less servers while preserving the preferred DAS access model for boot and swap storage.
I/O virtualization enables a server to be provisioned with as much or as little I/O – and of the right type – as its applications require, be it 1 Gb/s or 50 Gb/s; SAN, LAN, WAN, DAS or IPC. FCoE on its own still only provides a fixed (at server built time) aggregate bandwidth pipe of typically 10Gb/s per server irrespective of the application needs.
Without I/O virtualization, an FCoE connection is therefore still likely to be either over-subscribed which will compromise application performance, or underutilised leading to wasted expenditure and power. I/O Virtualization reduces both acquisition and running costs of servers while increasing the agility of the data center in the face of rapidly changing workloads and business requirements.
I/O Virtualization using PCI Express delivers the industry’s best server I/O price/performance and lowest energy consumption for accessing network and storage infrastructures through traditional or converged networks.
Tags: Virtualization, Cloud Storage, Data Centres