I recently attended a webcast where Jordan Plawner of Intel and Suzanne Morgan of Microsoft described how the combination of Intel Ethernet Server Adapters, Microsoft Windows Server 2008 R2 and Intel Xeon processor 5500 series-based servers are integrated to optimize iSCSI performance and scalability. I came away from a follow-up briefing with Jordan and Suzanne impressed with the potential benefits to large data centers, as well as the breadth of integration between Intel and Microsoft products. I was also reminded of the power of the Wintel formula. Intel and Microsoft have essentially overhauled iSCSI for the enterprise.
The term "Wintel" is commonly used to refer to a computer with some version of Microsoft Windows running on an x86 compatible from Intel. Since the late 80s when the symbiotic relationship between the two companies started to blossom, end-users have benefited from the powerful but low-cost computing platform the two companies maintain. The key ingredient of the Wintel formula is tight collaboration between Intel and Microsoft. For example, Windows 7 spreads its work across Xeon cores to minimize energy usage and to maximize performance. If one core is sitting idle, Windows sends more work to the idle core. If there is no extra work, the system will power down the core and save energy.
What many people don't know is that a secret weapon for converged networking has been at work since the advent of iSCSI. Long before the FCoE protocol was invented, iSCSI provided the ability to easily converge LAN and SAN traffic over Ethernet. Powerful, low-cost, out-of-the-box Wintel SANs have been available since Microsoft delivered an iSCSI software initiator in June 2003, shortly after ratification of the iSCSI protocol within IETF. Microsoft's goal with iSCSI support was to bring high-end SAN features to a broader set of customers, thereby increasing the potential SAN attach install base with Windows. In just six years, iSCSI arrays now represent about 30 percent of the SAN array and host adapter volume with approximately 90,000 iSCSI storage arrays and 900,000 host ports installed in 2009. Thanks to iSCSI and the Wintel formula, mainstream converged networking is a reality.
The iSCSI SANs have been widely recognized mostly for their ease-of-use and low cost, but a barrier to the deployment of iSCSI SANs in large data centers has been the 1Gb bandwidth of iSCSI compared to the 8Gb bandwidth of Fibre Channel. That obstacle is being cleared by 10Gb iSCSI. I expect the availability of 10Gb iSCSI arrays to drive continued rapid growth for iSCSI storage as data center managers upgrade their networks to 10Gb Ethernet. Looking forward, 40/100GbE should position iSCSI to open up an even wider lead on the next generation of 16Gb Fibre Channel.
One dominant initiative in almost every large data center is increasing operational efficiency by consolidating infrastructure. Three key technology trends behind infrastructure consolidation are increasing server utilization with server virtualization, sharing storage with SANs, and the convergence of LANs and SANs on 10Gb Ethernet. Intel and Microsoft accounted for all three technology trends and together overhauled iSCSI for use in the enterprise.
For starters, Intel Xeon 5500 processors are capable of handling an order of magnitude more I/O than previous generations of processors. Add multiple cores, and iSCSI workloads can now be distributed to utilize all the cores. Then to harness all that power, the Microsoft iSCSI software initiator in Windows 2008 R2 is "multi-core," which means it can scale to distribute I/O to as many as 256 cores. For customers using iSCSI digest for extended data integrity checking, Server 2008 R2/Windows 7 now offers digest offload directly to the CPU through a new industry standard CRC intrinsic, which is also supported on Intel processors and results in a 30 percent improvement in CPU efficiency using digests. It works transparently and auto-configures and isn't tied directly to any specific NIC implementation.
Finally, the Intel 82599 10Gb Ethernet adapter offloads some or all of CRC Digest, TCP/IP and IPsec processing so the server can be free to do processing related to the business application was purchased for. The proof-point for the new performance and scalability of iSCSI and Intel Ethernet server adapters was record shattering iSCSI performance of over 1 million inputs and outputs per second (IOPS) with native Windows Server 2008 R2. To put this level of iSCSI performance into perspective, that's double the IOP performance of the fastest 8Gb Fibre Channel host bus adapter available today. By the way, concerns around iSCSI performance rarely come from real-life experience. Customers using 1Gb Ethernet typically don't experience performance bottlenecks. When they do it's commonly disk, or the effective number of spindles supporting the LUN that limits overall I/O performance. Additionally, most are following the best practices of deploying multi-pathing and load-balancing. This allows the system or storage administrator to expand support for iSCSI traffic to at least 2Gb of aggregate bandwidth and up to 32 paths per LUN.
Microsoft enhanced support for iSCSI in Windows Server 2008 by reducing the overhead previously associated with running iSCSI from within the Hyper-V VM. Customers who require advanced SAN features and flexibility such as transportable snapshots, LUN cloning, application level synchronization and guest clustering tend to prefer using the iSCSI software initiator in the VM, as it allows applications, such as SQL to control data disks, to easily add/remove new LUNs without requiring administration from the Hyper-V administrator. When migrating from physical to virtual, iSCSI data LUNs migrate to the guest transparently without having to reconfigure disks on the parent. This mode also supports data encryption at the disk level from the context of the VM.
In addition, Intel 82599 Ethernet Adapters now support Microsoft Virtual Machine Queue (VMQ) to improve network throughput by distributing processing of network traffic for multiple VMs among multiple processors. Intel 82599 Ethernet adapters also include a feature called Virtual Machine Device Queues (VMDq) that works with Windows to offload virtual machine maps to the Intel adapter. The results are near-native iSCSI performance of 715,000 IOPS with Microsoft Hyper-V and dramatically lower CPU utilization.
The advancements in System Center Virtual Machine Manager to integrate the management experience of iSCSI and support a broader range of iSCSI targets are an added benefit to scale iSCSI deployments in the datacenter with Hyper-V.
The Intel 82599 Ethernet adapters shipping today feature 10Gb Converged Enhanced Ethernet (CEE), the foundation of networks of the future that will unify LANs, iSCSI SANs and Fibre Channel SANs. The latest in a battle-hardened line of 10Gb Ethernet adapters and LAN-on-Motherboard (LOM) products that have been shipping since 2007, the Intel 82599 is optimized for use with the trusted iSCSI software initiator in-box with Windows 2008 R2. Doing their part to help large data center managers converge LANs and iSCSI SANs, Microsoft has beefed up support for iSCSI remote boot by increasing redundancy for booting up to 32 simultaneous paths per target. This is a nice complement to the integration of boot support released in Server 2008 allowing remote install directly to an iSCSI disk.
The performance of the new Wintel iSCSI solution is impressive, but the benefits of iSCSI extend far beyond new performance levels. iSCSI features such as native security through mutual CHAP, IPsec, OS integrated remote boot and advanced data integrity through Digest Offload bring security and ease of management out-of-the-box to a broad range of customers.
The new power of iSCSI combined with superior ease-of-use and the ability to leverage existing investments in Ethernet will be attractive to data center administrators who require the flexibility of SANs in both physical and virtual environments. The Wintel formula still works. Intel and Microsoft have done an amazing job of integrating processor, operating system and network adapter to deliver an out-of-the-box, enterprise-class, iSCSI storage network solution that is going to be very hard to beat.
