I/O Consolidation

In our previous article, we showed that thanks to multi-queue technology, 10G Ethernet can deliver about 9 Gbit/s per second. We compared it with the typical link aggregated quad-port gigabit “NIC”. Quad-port link aggregation (IEEE 802.3 ad) is considered the “sweet spot”, both from a performance and an economic point of view. The results made 10G Ethernet really attractive: 10Gbit Ethernet actually consumed less CPU cycles than the quad-port link aggregated solution while delivering more than twice the bandwidth (9.5 Gbit/s vs 3.8 Gbit/s). It also features lower latency than quad-port NICs.

And 10G is hardly expensive: the least expensive dual 10G NICs cost about 50% ($600-700) more than the quad-port gigabit NICS ($400-450). Even the more expensive 10G cards (>$1000) offer a competitive bandwidth (2x 10G) per dollar ratio and offer a much better performance per watt ratio too. Typical power usage of dual 10G card is between 6W to 14W. The best quad gigabit NICs go as low as 4.3 W, although 8.4W is also possible.

10G Ethernet is much more than “a bigger pipe” for your (virtualized) network traffic. Let our knowledgeable IT professionals commenting on our last 10G Ethernet article enlighten you:

“In the market for a new SAN for a server in preparation for a consolidation/virtualization move, one of my RFP requirements was for 10GbE capabilities now. Some peers of mine have questioned this requirement stating there is enough bandwidth with etherchanneled 4Gb NICs and FC would be the better option if that is not enough. The biggest benefit for 10Gb is not bandwidth, it's port consolidation, thus reducing total cost.

To understand this just look at the picture below.

A virtualized server might need I/O ports for:

  • Console and management traffic (Ethernet)
  • VM migration (Ethernet)
  • VM Application network I/O (Ethernet)
  • Block Storage I/O (Fibre Channel)
  • File Storage I/O (Ethernet)

For speed and availability reasons, you quickly end up with two ports for each traffic flow, so you might end up with up to 10 ports coming out of one server. You might even need more: an IP based KVM to access the physical host and another port for server management interface (ILO, DRAC…).

Cleaning Up the Cable Mess
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  • fr500 - Wednesday, November 24, 2010 - link

    I guess there is LACP or PAGP and some propietary solution.

    A quick google told me it's called cross-module trunking.
  • mlambert - Wednesday, November 24, 2010 - link

    FCoE, iSCSI (*not that you would, but you could), FC, and IP all across the same link. Cisco offers VCP LACP with CNA as well. 2 links per server, 2 links per storage controller, thats not many cables.
  • mlambert - Wednesday, November 24, 2010 - link

    I meant VPC and Cisco is the only one that offers it today. I'm sure Brocade will in the near future.
  • Zok - Friday, November 26, 2010 - link

    Brocade's been doing this for a while with the Brocade 8000 (similar to the Nexus 5000), but their new new VDX series takes it a step further for FCoE.
  • Havor - Wednesday, November 24, 2010 - link

    Do these network adapters are real nice for servers, don't need a manged NIC, i just really want affordable 10Gbit over UTP ore STP.

    Even if its only 30~40M / 100ft because just like whit 100Mbit network in the old days my HDs are more then a little out preforming my network.

    Wondering when 10Gbit will become common on mobos.
  • Krobar - Thursday, November 25, 2010 - link

    Hi Johan,

    Wanted to say nice article first of all, you pretty much make the IT/Pro section what it is.

    In the descriptions of the cards and conclusion you didnt mention Solarflares "Legacy" Xen netfront support. This only works for paravirt Linux VMs and requires a couple of extra options at kernal compile time but it run like a train and requires no special hardware support from the motherboard at all. None of the other brands support this.
  • marraco - Thursday, November 25, 2010 - link

    I once made a resume of total cost of the network on the building where I work.

    Total cost of network cables was far larger than the cost of the equipment (at least with my country prices). Also, solving any cable related problem was a complete hell. The cables were hundreds, all entangled over the false roof.

    I would happily replace all that for 2 of tree cables with cheap switches at the end. Selling the cables would pay for new equipment and even give a profit.

    Each computer has his own cable to the central switch. A crazy design.
  • mino - Thursday, November 25, 2010 - link

    IF you go 10G for cable consolidation, you better forget about cheap switches.

    The real saving are in the manpower, not the cables themselves.
  • myxiplx - Thursday, November 25, 2010 - link

    If you're using a Supermicro Twin2, why don't you use the option for the on board Mellanox ConnectX-2? Supermicro have informed me that with a firmware update these will act as 10G Ethernet cards, and Mellanox's 10G Ethernet range has full support for SR-IOV:

    Main product page:

    Native support in XenServer 5:
  • AeroWB - Thursday, November 25, 2010 - link

    Nice Article,

    It is great to see more test around virtual environments. What surprises me a little bit is that at the start of the article you say that ESXi and Hyper-V do not support SR-IOV yet. So I was kind of expecting a test with Citrix Xenserver to show the advantages of that. Unfortunately it's not there. I hope you can do that in the near future.
    I work with both Vmware ESX and Citrix XenServer we have a live setup of both. We started with ESX and later added a XenServer system, but as XenServer is getting more mature and gets more and more features we probably replace the ESX setup with XenServer (as it is much much cheaper) when maintenance runs out in about one year so I'm really interested in tests on that platform.

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