This page contains a Flash digital edition of a book.
Accelerate Performance with Seamless Networking Consider the network adapters for iSCSI. Traditional

network adapters can impose significant processor overhead. This might not seem like a major concern for today’s multicore processors, but there are several technologies available to ease processor overhead and vastly improve iSCSI performance, especially when mixing storage and non-storage traffic on the same LAN. The best approach is to adopt enterprise-class “offload-capable” network adapters that provide TCP/IP offload or iSCSI offload capabilities.

TCP/IP offload capabilities are not new—in essence,

the “offload” implements the TCP/IP stack in the network adapter’s hardware, alleviating those tasks from the processor. Many modern network adapters implement the more recent Microsoft TCP Chimney offload architecture available in all versions of Windows Server 2008, which also handles IPv4 and IPv6 connections. However, TCP Chimney may not be compatible with Hyper-V. TCP/IP offload-capable NICs are available for GbE and 10GbE, and will help accelerate all types of network communication.

Similarly, network devices with iSCSI offload

capabilities include their own iSCSI initiator hardware on the adapter that handles iSCSI traffic specifically. Host bus adapters with iSCSI offload are available for GbE and 10GbE LANs.

Optimize Processes to Reduce Overhead and Increase Efficiency Enable jumbo frames for iSCSI. Use network devices

(adapters, switches, routers, storage targets, and so on) that support jumbo frames. A normal Ethernet frame encapsulates a 1,500-byte payload in addition to the overhead of the frame. The overhead helps systems sort and reorder the frames and request resends when frames are missing or damaged. As a consequence, a great many individual frames (and a substantial amount of overhead) may be needed to transfer a file or other data across the network.

Jumbo frames allow a much bigger data payload in

each Ethernet frame, and typical jumbo frames may transfer 4,000, 9,000, or even 14,000 bytes of data in each frame. This means the amount of overhead versus the data is much smaller, making the data exchange more efficient. However, each physical and virtual element in the network must support the same jumbo frame size. If not, noncompliant components will need to be upgraded (or the frame size adjusted) to achieve end-to-end compatibility.

Take Advantage of Multi-Core Processing Power Adopt Receive-Side Scaling technology. You’ve already

seen that TCP/IP can place a burden on a processor, but an additional problem is that TCP/IP uses the same one processor core—it does not spread out the workload among multiple cores. This is due to the legacy design

of the TCP/IP stack (from the days of single-core processors). Receive-Side Scaling (RSS) capability in the network adapter overcomes this problem by balancing incoming network frames across various processor cores. It is not a critical technology (especially if offload-type adapters are used) but it is strongly encouraged as a best practice for iSCSI.

Segregate the storage and LAN traffic. Although iSCSI

allows storage and regular LAN traffic to share the same physical network, some organizations may still opt to separate the storage and non-storage traffic using virtual LANs (VLANs) or separate physical networks. This is particularly important in GbE LANs, but may not be essential in all 10GbE networks.

For example, a VLAN allows a single physical network to

be segregated into two or more logical networks. This is an ideal means of separating storage traffic from non-storage traffic, ensuring that storage traffic is only available to the server and storage subsystems.

It is also possible to create a separate physical LAN that

is dedicated to storage traffic. This would include separate network adapters, cabling, switches, and so on. This is the costliest option because the physical LAN elements are duplicated, but it also supplies full network bandwidth to storage. It also provides the best security because there is no chance for storage and non-storage data to mix on the same wires.

ABOUT THE AUTHOR: Stephen J. Bigelow, Senior Technology Editor in the Data Center and Virtualization Media Group at TechTarget Inc., has more than 20 years of technical writing experience in the PC/technology industry. He holds a bachelor of science in electrical engineering, along with CompTIA A+, Network+, Security+ and Server+ certifications and has written hundreds of articles and more than 15 feature books on computer troubleshooting, including Bigelow’s PC Hardware Desk Reference and Bigelow’s PC Hardware Annoyances.


How Healthy Is Your Storage? Optimize Your Storage Investment with a Healthcheck

Managing your organization’s data is an ever-present challenge. As the amount of data your users create continues to grow, so does the need for a storage environment that operates at maximum efficiency. PC Connection’s Storage Healthcheck Service is available to help you optimize your initial investment and get the most out of your existing storage approach.

Designed to review your current storage infrastructure and analyze its performance and capacity utilization, our service delivers the facts you need to make informed investment decisions. A Healthcheck helps your organization reduce costs, shorten backup/ recovery times, and improve overall operational efficiency.

Call your Account Manager to schedule a Storage Healthcheck today! 1.800.800.0014



Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36