StorageMojo




Robin Harris    


Hot new 10Gb switch will shake up storage networks

April 17th, 2007 by Robin Harris in Clusters, Enterprise, SAN, FC

This morning Woven Systems announced their new 10 Gbit Ethernet switch. I named Woven “coolest hardware” at last years Datacenter Ventures conference. Harry Quackenboss, their CEO, promised they’d have the switch working in six months. Well, here it is a mere seven months later, and they’ve done it. My hats off to the engineering team.

Now let’s get into Woven’s Mojo.

I’d rather switch than fight
The switch is unique is several respects:

  • 10 Gigabit ethernet only
  • Up to 144 non-blocking ports on a single switch
  • Up to 4,000 non-blocking ports in a fabric of Woven switches
  • Built from commodity parts - with one vital exception
  • Low-cost
  • The killer feature: active congestion management
  • Uses standard ethernet protocols

What is it going to kill?
It shouldn’t be a surprise that fibre channel has some features that storage systems find really useful. After all, FC was developed as a storage interconnect. So it has bandwidth, flow control, low latency and rapid failover.

Gigabit ethernet lacks in all these areas: limited bandwidth; lost packets in congested networks; high IP latency; and failover that is too slow for storage drivers to manage.

It looks like Woven has solved 3 of the 4
Woven’s secret sauce is built into an ASIC that sits in front of the commodity 24 port ethernet chip (picture helpfully provided by Woven).

Woven switch blade

The vScale Packet Processor - I don’t know what the “v” stands for - inserts low-overhead probe packets into the data stream, which the vPP at the other end of the stream, be it in the same switch or one across a fabric, bounces back, so the originating vPP has a real-time view of path latency. In milliseconds or less. It works across a fabric of up to 4,000 ports, ensuring that QoS even as the fabric grows.

That’s pretty cool, but the coolest thing is this:
When path latency is too high, the vPP has two tools it uses to manage the latency.

  • It can change to a less congested data path in less than 10ms
  • It can pause the HBA using a standard ethernet protocol

I know what you are thinking:
Wow, path failover in 10ms - drivers won’t even notice.
And
Pausing HBAs when congestion strikes is flow control for ethernet - a process FC handles with buffer credits.
All done using standard ethernet protocols, albeit creatively.

That bell you hear is tolling for Fibre Channel, which is about to meet its toughest competitor yet. Which may be why the FC over ethernet proposals are gathering steam in the T11 committee. Adding FC’s low latency protocol to a very fast and reliable 10 Gb switch adds real value and helps protect existing FC investment. Could be a nice win for all involved.

The StorageMojo take
I’m sure all the usual Internet Data Center suspects are lined up to beta Woven’s switch. Linking several hundred thousand servers via ethernet requires a lot of bandwidth, and 10GigE delivers. For the massive storage clusters it is an even bigger win: lost packets are still a pain even if the cluster can survive them.

If everything works as advertised, FC’s decline may be faster than forecast, at least among the large enterprise base that can use a switch of this size. Woven’s switch will be a shot in the arm for big clusters and the people who build them.

Update: I’d inadvertently left out the fact that you can cross-couple the switches to create a 4,000 port fabric so I’ve added it.

Update II: Harry, Woven’s CEO, helpfully added some budget pricing for all you folks with new fiscal years starting mid-year - like the Cisco tear-down guys - and I couldn’t just leave it buried in the comments.

Pricing will be finalized when general availability is announced (planned for Q3 2007), but a 144 10GE port configuration will be about $1500/10GE port, with fully-redundant fans, power supplies, and management cards.

Compare that to Cisco’s current $23k/port pricing and Riverstone’s very aggressive $10k/port pricing for full speed 10 Gb and the term “disruptive technology” just leaps to mind.

Comments welcome, of course. I spent six hours at NAB today and drove over 1,000 km, so moderation may be a bit sluggish today. Me too.

9 Responses to ' Hot new 10Gb switch will shake up storage networks '

Subscribe to comments with RSS or TrackBack to ' Hot new 10Gb switch will shake up storage networks '.

  1. Wes Felter said,

    on April 17th, 2007 at 12:04 pm

    It would be interesting to compare the price and performance of the Woven and Quadrics switches.

  2. Tracy R Reed said,

    on April 17th, 2007 at 11:46 pm

    Sounds great. So how much and when can I buy one?

  3. andrew said,

    on April 19th, 2007 at 5:21 am

    interesting indeed - This will be hot year for switch gear!


  4. on April 19th, 2007 at 11:10 am

    I understand that an individual port can run at 10Gb, but what is the aggregate bandwidth for all 12 ports on the above board? Can they all run 10Gb sustained simultaneously?

  5. Harry said,

    on April 20th, 2007 at 6:55 am

    On a line card, 12 ports can transmit and receive 10Gb simultaneously. Within a chassis, 144 ports can do so, for a switch fabric bandwith in the chassis of 2.88 terabits/sec (144*10GE*2) Using a two-stage “fat tree” fabric of 144 port chassis, 4000+ ports can transmit and receive simultaneously with full cross section bandwidth.


  6. on April 22nd, 2007 at 10:37 pm

    Let me know when you find out the price Tracy.

  7. Tom said,

    on April 23rd, 2007 at 10:06 am

    Nathan, this article said 750£ per port…
    http://www.techworld.com/news/index.cfm?rss&newsid=8605

  8. Harry said,

    on April 23rd, 2007 at 2:46 pm

    Pricing will be finalized when general availability is announced (planned for Q3 2007), but a 144 10GE port configuration will be about $1500/10GE port, with fully-redundant fans, power supplies, and management cards.

  9. Daniel said,

    on June 26th, 2008 at 8:37 am

    I have recently (re)joined Quadrics. I *do* have pricing for our 10GigE swicthes if folk are interested.

    I know it is a year-on from the previous postings - but our price per port is a fraction 0f that quoted for Woven’s

Leave a reply



StorageMojo RSS Feed July 2008 June 2008 May 2008 April 2008 March 2008 February 2008 January 2008 December 2007 November 2007 October 2007 September 2007 August 2007 July 2007 June 2007 May 2007 April 2007 March 2007 February 2007 January 2007 December 2006 November 2006 October 2006 September 2006 August 2006 July 2006 June 2006 May 2006 April 2006 March 2006 June 2005 April 2005 March 2005 February 2005 January 2005 December 2004 November 2004 October 2004 September 2004