Tuesday, March 29, 2011


The ATA over Ethernet (AoE) protocol provides a method of carrying Storage Area Network (SAN) traffic over a switched Ethernet network. AoE provides networked storage that supports virtualization and cloud computing applications.

An AoE SAN consists of commodity hardware: SATA disks, Ethernet adapters and switches. The result is a low cost, high performance networked storage solution. The article, What is Ethernet SAN & AoE?, includes technical details and a discussion of the benefits of AoE as a SAN technology.

Visibility into network activity is essential for maintaining optimal performance in a converged network since storage traffic  tends to dominate network workloads. Fortunately, one of the benefits of using an Ethernet SAN is increased network visibility since most switch vendors implement the sFlow standard in their switch hardware.

One of the unique features of the sFlow standard is that any sFlow capable switch will monitor all types of traffic flowing across the network, including non-IP SAN protocols such as AoE and FCoE. The sFlow data exported by the switches includes packet header information that permits an sFlow analyzer to report on new types of traffic as they are deployed on the network without any need to upgrade switch firmware or hardware.

The following chart trends AoE operations on a SAN using sFlow data from Ethernet switches:

The chart shows the detailed visibility into AoE servers, clients, operations and targets available through sFlow monitoring. In addition, sFlow is being used to monitor the performance of the systems attached to the Ethernet SAN. Using sFlow to monitor servers links MAC addresses associated with AoE connections to server host names, UUIDs and performance metrics. The chart above demonstrates the additional context that integrated network and server monitoring provides; showing that while there are two different server MAC addresses (FAA69ECD3D6F and EABF12E86CD0), they are in fact associated with a single storage server (UUID e9d0e087-51c7-429e-9841-4439db35f3be).

The following charts make use of sFlow data from the server to trend server load:

In this case, it appears that the storage server is the performance bottleneck. Upgrading the server, or moving to a dedicated AoE storage appliance (e.g. Coraid EtherDrive) should significantly boost performance.

Network convergence using a high-speed, flat, layer 2 fabric creates a simple, flexible infrastructure that supports virtualization and cloud computing. Choosing switches that support the sFlow standard provides the unified view of network and system performance needed for effective control of data center resources. For additional information, the Data center convergence, visibility and control presentation describes the critical role that measurement plays in managing costs and optimizing performance.


  1. is there any tool for converting sflow v2 to sflow v5 or netflow

  2. sflowtool can convert sFlow v2 to NetFlow v5. With any sFlow to NetFlow conversion there is a considerable loss of information. The best solution is to use a traffic analyzer that natively supports sFlow - many handle both sFlow and NetFlow data sources.

  3. @Peter thanks..
    sflowtool -c localhost -d

    is this the command ?

  4. The NetFlow related arguments for sflowtool are:

    -c hostname_or_IP - (netflow collector host)
    -d port - (netflow collector UDP port)
    -e - (netflow collector peer_as (default = origin_as))
    -s - (disable scaling of netflow output by sampling rate)
    -S - spoof source of netflow packets to input agent IP

    You need to provide a UDP port number as an argument with the -d flag. If you are receiving sFlow from more than one switch then you will want to use the -S argument to spoof the IP sources addresses in the NetFlow to match the original switch IP addresses.