Brocade Performance

The Brocade DCX Backbone is the highest performing modular switch in the industry, supporting full speed 8-Gbps on every port without frame loss or error.

Miercom recently published the attached report providing an independent analysis of the Brocade DCX Backbone and competitive comparison with the Cisco MDS director-class switches (9513 and 9509).

Testing focused on maximum aggregate throughput and scalability using 8-Gbps traffic generators, along with real-world 8-Gbps application traffic. In-depth analysis of power consumption, reliability, and management was also conducted.

Based upon these test results, the Brocade DCX Backbone was rated best in scalability, throughput, and energy efficiency, and proved to have "very effective high availability capabilities".  Quotes from the February 2009 Miercom Lab Test Report include:

• "The Brocade DCX proved in testing to offer four times the number of ports that can be used for dedicated 8-Gbps line rate traffic simultaneously compared to the Cisco MDS 9513"
• "Brocade DCX passed the industry's first 128 port full 8-Gbps Fibre Channel test without frame loss"
• "The Brocade DCX proved more capacity than the Cisco MDS 9509 and 9513 on tests for overall aggregate throughput"
• "The Brocade DCX reflects an almost three times reduction in power consumption when compared to the Cisco MDS 9513"
• "The Brocade DCX is clearly designed to exceed data center customers' reliability expectations"
• "Two DCX switches could interconnect using up to four ICLs with no ports sacrificed to provide capacity for up to 768 ports of 8-Gbps Fibre Channel"
• "The DCX with two 48-port 8-Gbps blades delivered full line rate performance using the 256-Gbps slot-backplane bandwidth available combined with local switching"
• "DCFM (Data Center Fabric Manager) is an effective tool to assist administrators to optimize storage resources, maximize performance of the system and help maintain security"

This test report is available from Miercom's web site. An executive summary is also available for download.

The Brocade DCX supports 4 times the number of 8-Gbps ports as the Cisco MDS 9513, even without local switching.

Miercom conducted 18-hour attrition and maximum OX-ID stress tests and verified that the Brocade DCX Backbone delivers frames in proper sequence with no frames dropped. The Brocade DCX was in the default configuration (aptpolicy=3), which utilizes Exchange Based Routing internally to maximize performance. Testing was conducted using a Finisar Xgig Load Tester and the proper "Fixed/Unique" test mode as documented at www.finisar.com/library1_6_2.

The stress tests were also monitored and reviewed by the Finisar technical staff.

Brocade has also created an 18 minute video demonstrating the DCX undergoing the "8-Gbps torture test" of 64 ports of 8-Gbps running full-mesh at various frame sizes. The DCX passes with flying colors, showing neither frame loss nor congestion. In addition to this stress test, Exchange, Oracle and VMWare I/O are run on additional ports, again with no frame loss, congestion, application disruption or outages.

DCX Full-Speed 8-Gbps Performance Test, No Congestion, No Frame Loss (Quicktime, 151 MB)
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DCX Full-Speed 8-Gbps Transcript (PDF, 68 KB)

When using Fibre Channel frame shooters, it is important to understand the parameters of the tester and equipment being tested.

Finisar has issued a technical support note stating that their XGig frame shooter set to "Random OX_ID" mode incorrectly reports errors and dropped frames when used with a DCX or 48000 running aptPolicy=3. Finisar documentation provides a clear and definitive statement that any errors or dropped frames shown when using atpPolicy3 are inaccurate:

The Random and Incrementing OX_ID test modes send test frames that vary the OX_ID of each frame being sent. Random or Incrementing OX_ID modes can be used to test for single-frame exchanges that are received in an order different than how they were transmitted. Testing in this configuration, however, requires the understanding that the column headings named "Dropped Frames"and "Sequence Errors" must be ignored.
"Using Finisar Xgig Fibre Channel Load Tester with SAN Equipment"

What does In-Order Delivery really mean in the context of Fibre Channel Storage Area Networks? Read about it in this white paper:
  Fibre Channel In-Order Delivery (PDF, 500 KB)

The Fibre Channel (FC) standards require that fabrics deliver frames in the same order that they entered the fabric. That is, a network of FC switches should act like a FIFO buffer, from the point of view of attached devices. This requirement is called “in-order delivery”, or IOD for short. However, the language in the standards describing IOD is ambiguous, and so there is confusion about what IOD means. There are situations in which out-of-order delivery (OOD) is allowable, and even desirable. In other cases, OOD may have a strongly negative impact on applications attached to an FC Storage Area Network (SAN).

To analyze fabric IOD requirements, it is necessary to consider which traffic patterns require delivery order to be maintained, and why this is required in the first place. In most environments, FC networks are used to carry SCSI traffic. In this context, IOD means “all FC frames within a particular SCSI operation must be delivered in order with respect to each other.” FC frames in different, unrelated SCSI operations do not need to be delivered in order relative to each other. In fact, it may be desirable to prioritize one SCSI operation over another: that is the purpose of QoS and similar features. In that case, the entire point is to make sure that higher priority frames are delivered ahead of lower priority traffic, regardless of which entered the fabric first, which by its nature is OOD.

This paper will clarify what In Order Delivery means in an FC fabric, so readers can identify situations in which it is meaningful and required vs. optional or even undesirable.

How Does DCX Performance and Scalability Benefit Customers?

The Brocade DCX provides greater return for enterprise data centers. The performance, scalability, and energy efficiency advantages of the Brocade DCX Backbone over the Cisco MDS 9513 and 9509 are significant and, complemented by Brocade DCFM, enable enterprise data centers to:

• Achieve greater consolidation of servers, storage, networks, and data centers themselves
• Enable Broaden server virtualization through more (and more demanding) virtual machines on fewer physical servers, with higher resource utilization
• Scale fabrics much more efficiently and non-disruptively (with up to 768 ports at full 8-Gbpsspeed in a standard rack) without increasing complexity and footprint
• Free up more power and cooling resources (with a 10x advantage based on Watts/Gbit/sec) for servers and storage arrays
• Reduce equipment, facility, overhead, and energy costs to a far greater degree

Click here for references.