Riverbed Steelhead boosts WAN data flow

IT always seems to be caught in the middle of the WAN-performance battle: On one hand, users never seem to be happy with an application’s performance; on the other, the bean counters won’t budget for bigger pipes. If more bandwidth isn’t the answer to end-users’ performance problems, then what is?

Free IT resource Virtualization Insights from Top Experts - Learn how virtualization gets real! Sponsored by Dell Free IT resource Try Sun servers, workstations and storage products free for 60-days. Sponsored by Sun Microsystems TEST CENTER DAILY BLOG Track the latest product reviews and news from the InfoWorld Test Center. Riverbed Steelhead with RiOS 3.0 Riverbed Technology, riverbed.com Excellent  9.0 criteria score weight Performance 9 40% Protocol support 9 25% Reliability 9 15% Setup 9 10% Value 9 10% Cost: Steelhead 200, $4,995; Steelhead 5520, $69,995; Steelhead 6020, $119,995 Platforms: Any Ethernet-based network with TCP/IP and UDP traffic Bottom Line: Riverbed continues to impress with expanded CIFS and NFS support, allowing for better performance with both Windows- and NFS-based servers. QoS can now be enforced in the appliance with policies based on bandwidth and latency. Reporting also saw upgrades, as did the pre-population service to help eliminate cold hit penalties. Detection and correction of asymmetric routes is a definite plus. About our Reviews and Scoring Methodology

The solution to improving both response time and circuit utilization is to make the connection more efficient and to reduce the effects of latency. I’ve watched a whole new breed of WAN optimization and acceleration appliances come to market during the past few years, and I’ve seen firsthand what a difference intelligent optimization can make on WAN response time.

Once again, I had Riverbed's Steelhead WAN acceleration and optimization appliances on my test bed, and true to form, the company provided excellent improvements with little tweaking. Release 3 of the RiOS (Riverbed Optimization System) shows a more mature product, with the focus on improving existing features, the addition of greater application support, and much increased capacity. During its time on my bench, Steelhead proved again that it is more than capable of making oversubscribed WAN circuits appear faster than they were while greatly reducing response time, besting previous releases by as much as 20 percent.

I tested three Steelhead appliances: the 200, the 5520, and the 6020. The 5520 (offering 155Mbps of optimized throughput and 15,000 TCP connections) and the 6020 (boasting 310Mbps of optimized throughput and 40,000 TCP connections) are hardware platforms released this year -- as are their cousins, the 3020 and the 3520.

I set up the 5520 as the branch-office appliance and the 6020 as the datacenter unit. (The complete solution requires at least two appliances.) The impish 200 (1Mbps of optimized throughput and 100 TCP connections) came into play during testing of optimization of asymmetric routes (more on this later). My trusty Shunra VE simulated my various WAN conditions, and D-Link DGS-3324SR Gigabit switches tied it all together.

Click for larger view.

Maturing Gracefully

RiOS has always included optimizations for CIFS and MAPI aimed at reducing the protocols’ chattiness. In RiOS 3, Riverbed builds on this solid foundation with the addition of NFS streamlining. As with CIFS traffic, there is a lot of protocol overhead with NFS that can degrade application response time significantly. RiOS 2.1 performed NFS optimization via data and transport streaming; RiOS 3 does NFS application streaming, allowing for read-ahead and metadata pre-fetching. Unfortunately, I do not have any NFS performance numbers from previous releases, but Riverbed’s internal testing shows a 10-fold improvement in RiOS 3. CIFS traffic gained an improvement of between three and six times compared with last year’s testing.

CIFS traffic also received additional application-specific acceleration for programs -- such as SolidWorks, Visio 2003, and SolidEdge -- that open a file multiple times during a single operation. Previously, Steelhead would not optimize subsequent requests for the locked file, erring on the side of data integrity. The new CIFS mode, called overlapping opens, allows Steelhead to continue to optimize CIFS traffic even though Windows has the file locked, improving response times even under these conditions.