During Storage Field Day 6 we visited Coho Data HQ for the second time, and if you want to learn you really should watch the videos recorded during the event. First a bit of history on Coho Data which was founded by Andrew Warfield, Keir Fraser and Ramana Jonnala. And if you didn’t know these guys are known by a small thing called XenSource (later acquired by Citrix).

Coho Data introduced their new scale-out hybrid storage solution (NFS for VM workloads) during Storage Field Day 4 a year ago and is a regular Tech Field Day sponsor as they presented during Virtualization Field Day 3. Hybrid in the Coho Data product means they use a mix of PCIe Flash and SATA disks. As said the Flash devices used by CohoData are PCIe based  devices (Intel 910 800 GB to be exact, but due to the Coho Data architecture this can be changed easy and the Intel devices are the second kind of flash devices Coho uses in the array, first were Micron).COHO1

As you can see in the picture above the Coho Data is build up of  a 2U box holding 2 “MicroArrays” that each have  2 CPUs, 2 x 10GbE NIC port and 2 PCIe INTEL Flash cards. With this configuration a 2U block provides 39TB of capacity and around 180K IOPS (Random 80/20 read/write, 4K block size). The Coho Data product offers deduplication and compression as well as replication, High Availabilty and Snapshot technology  in their offering . Last but certainly not least, it comes with an OpenFlow-enabled 10GbE switch (Arista) to allow ease of management, scalability and the opportunity to Streamline the data streams.

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Diving deeper into the Coho Data DataStream architecture  reveals the IO lane technology uses: 10GbE NIC <-> CPU <-> PCIe Flash. All IO lanes have their own CPU,  10 GbE NIC Port and a 800 GB Intel PCIe Flash . With this architecture Coho Data created an easy to scale, high performance storage system. By using the Openflow enabled SDN switch to manage the streams within the whole DataStream environment and giving the customer a SDS solution with the Coho Data MicroArray this is storage at it best.

I hear you think: “what about setting it up and managing the Coho Data offering? It’s probably extremely hard to setup and manage this system.” But it isn’t. You could setup the Coho Data system in about 15 minutes, and once your done you can use the UI to manage and maintain the system easily. Just take a look at the picture below and make sure to watch the Tech Field Day videos to see more on the UI.

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What’s the future for Coho Data?

During the presentation there were a couple of questions going around in my head, but because listening to Andy presenting is taking almost all of my brain resources I didn’t ask then. That should be that big of problem, so I asked the questions through mail when I was back in the Netherlands and here are the questions and answers:

Q.You mentioned that with 1 PCIe flash device you were able to saturate a 10 Gig NIC. I understand the PCIe performance is more than sufficient for the CohoData product, but are you already looking at things like Diablo’s MCS? I know it’s still new technology with it’s own pros and negatives, but still I thought in some cases this might be a great solution for Coho. What’s your opinion?

A. The reason that I talked about NVDIMM in the second part of my presentation is that I really see RAM speed memories starting to become more and more practical in storage systems from about 2016/2017 onwards.  The data path work that we are doing is really focussed towards these: PCIe flash is fast enough to saturate the 10Gb interface, but mostly with large requests on today’s hardware.  As we move to NVDIMM and related technologies like Diablo’sstuff (which is really, really cool BTW), the biggest overheads will be the (software) data path processing to do file system layout, replication, snapshots, placement, recovery, etc.


The work that Coho is doing here, both on the host and in the network, is one of the biggest differences between us and other companies.  I think it’s really going to start to show over the next couple of years.

If you look at the left picture (taken last year) and the right picture (taken during the SFD6 presentation) it seems AFA and cold data systems will be added…

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Q.  One of the slides showed a cluster of Coho arrays and it was interesting to see normal arrays as an all HDD (archiving/object store??) array. Is this what you’re looking at? And maybe even further are you also looking at AFA’s for demanding workloads, or is this not needed at all with Coho?

A.   Ah — you found the (unintentional) easter egg!  I totally forgot to mention this in my presentation!


In 2015 we will roll out 2 new appliance versions.  One will be a “hybrid flash” chassis that combines PCIe flash with SAS flash.  It will be performance focussed and still have all the transparent scale-out properties of our existing boxes.  It will also be able to install into an existing hybrid-disk/flash based coho install.


The second new box, which we are planning for 2H 2015 is a capacity box that is a 2-server, 70-disk 4u.  It will have between 250 and 500 TB raw capacity, and serve as bulk storage for cold data.


For large installs, these two boxes will allow customers to scale capacity and performance completely independently of one another.

There is so much more to be told about Coho Data but that’s for a later time. For now…. Let’s have weekend!!! Have a great one and CU again soon!!

Other delegates on Coho Data:

And always make sure  to watch the Tech Field Day of a Sponsor, as there is always tons of information to be found there:

Coho Data Page at Tech Field Day