The Need for Interface Speed - How Much is Enough?

 

 

 

 

Today there is support for 16GFC and 10GbE, and the next speed increases on the technology roadmap are 32GFC, and 40G Ethernet and FCoE.  The host and networks interfaces are always first to move to the higher speeds with storage systems transitioning last.  This chart summarizes a comparison between the speeds.

 

Speed

Clocking (Gbps)

Encoding (data/sent)

Data Rate (MBps)

8GFC

8.500

8b/10b

1600

10GFCoE

10.3125

64b/66b

2400

16GFC

14.025

64b/66b

3200

32GFC

28.050

64b/66b

6400

40GFCoE

41.225

64b/66b

9600

100GFCoE

103.125

64b/66b

24000

 

32GFC is expected to be available in 2014, and it’s expected that 40GFCoE and 100GFCoE which are based on 2010 standards will be used exclusively for Inter-Switch Link cores for the near future, thereby maintaining 10GFCoE as the predominant FCoE edge connection.

We all know that the volume and size of data is growing like crazy, but in many environments today’s current interface speeds are sufficient and not being fully utilized.  However, moving to a higher interface speed provides the following benefits:

  • Increased  throughput  (2-3x)
  • Reduced number of HBAs, NICs and switch ports required to achieve similar performance
  • Less cabling investment
  • Simplified manageability with reduced port counts
  • Less power consumption due to less HBAs, NICs and ports

What are your thoughts? Are current interface speeds sufficient or do we need 32GFC and 40GbE now?

 

Mike McNamara

Comments

Even for today's standards, we're slowly reaching a point where protocol speed increases will probably make more sense to be used as Targets than initiators. This is particularly true with the advent of Flash as an additional server side caching mechanism, where a significant amount of IO will not hit the wire.  Now the question is, whether storage arrays can sustain or even achieve, these levels of available throughput. An extremely difficult task for today's storage arrays.

Why not support FDR Infiniband?  It is available now.  I have never understood why Netapp has ignored FCoIB.

Lorie,  good question, but FDR Infiniband is not mainstream like FC and Ethernet and hard to justify.