Back in February of this year, when I read an article in The Register, announcing that Raghu Nambiar, the then chief technology officer for UCS servers had joined AMD. I didn’t think too much of it, but when I also saw that AMD were, for the first time (in my memory), exhibiting at Cisco Live, My right eyebrow rose in a particular “Roger Moore esque” manner, and I sensed something may well be afoot.

Some of you may well have noticed that even since 2009 there has always been an AMD CPU server qualification policy in Cisco UCS Manager , and several years ago I did bring this up with Cisco, as to why in an exclusively Intel based product would need such a policy, to which, if memory serves, the answer at the time was “never say never”

Well today that “prophecy”  was fulfilled with the announcement of the Cisco UCS C4200 chassis which can house up to 4 x C125 M5 server nodes which are exclusively AMD EPYC based.

C4200 containing 4 x C125 Server Nodes

Now I know what you are all probably thinking, a modular UCS server? didn’t Cisco already try this with the M-Series which they decided end of life back 2016. But the answer is NO! the M-Series was a completely different beast, which was geared around host “dis-aggregation” with larger numbers of much smaller spec hosts built upon the lower spec Intel XEON E3 CPUs, with shared I/O and shared disks not to mention the M-Series was UCSM managed only.

In contrast the C4200/C125 M5  has the following specs.

C4200 2 Rack Units chassis contains up to 4 x C125 M5 Server nodes
24 drives per C4200, 6 dedicated to each node, 2 of those 6 can be NVMe
2 x AMD EPYC 7100 Series CPUs up to 32 Cores each
Up to 2TB RAM per node
Up to 46.8 TB HDU per node (6 x 7.8 TB SSD)
2 x 2400W PSUs
Optional 4th Gen VIC 10/25/40/50/100Gbps  (to be released later this year.)
Plus the C125 can be managed by UCS Manager, UCS Central, from the Cloud with Cisco Intersight, Stand-a-lone CIMC, or 3rd Party tools.

C125 M5 Server Node

If there are 3 words that describe why Cisco have chosen the AMD EPYC CPU along with the modular form factor, they would be Density, Density and Density as it is possible to pack a whopping 128 Cores per Unit of rack space.  The graphic below compares density volumetrics against the UCS C220 rack mount server

But all these “speeds and feeds” stats are great, but what business requirements will these new servers address? and what particular workloads or industries will particularly benefit from them? Well as can be seen in the below graphic, Cisco are positioning the C125 for any compute intensive applications or where an exceptional amount of compute density is required, as well as Gaming/E-Gaming. And interestingly Cisco also list High Frequency Trading (HFT) and enterprise High Performance Compute (HPC) as a particular use case for the C125 markets that up until now Cisco had never actively targeted,  Which would explain the addition of the Open Compute Project (OCP) 2.0 Mez slot supporting options such as InfiniBand for ultra low latency networking..

Cisco UCS Portfolio

As ever with the Cisco UCS family it’s all about options and Flexability and while there are several “all rounder” options there are definitely sweet spots for certain UCS family members. Bill Shields of Cisco has produced a nice radar diagram below to guide you as to these sweet spots depending what use cases you are looking to address.

As you can see the C125 M5 wins out in the density areas, but if minimal cabling is a priority then Blades are a great option or the S3260 servers for maximum storage. The reality being that a combination of these servers may well be the best overall solution in many cases, hitting that optimised price point for each element of the solution.

Sharing that storage!

While Cisco have not announced any Software Defined Storage (SDS) option for the C125 I think it would also make a great Hyperconverged node and as Cisco already have HX Data Platform  in the portfolio it would make great sense to combine the 2. So who knows we may see Cisco “HyperFlex Up” the C125 M5 in the future. But in the meantime there is always the option to run an SDS solution like StorMagic or VMware VSAN if that’s the way you want to go. But of course traditional NAS and SAN solutions are also very valid storage options.

Closing thoughts

For me the big differentiation of Cisco UCS has always been the management Eco system.  It is a huge plus to be able to manage hundreds of servers as easy as one. And having that management platform available on premises or from the cloud and covering the whole UCS family regardless of whether they are blades, rack mounts, modular or Hyper-converged nodes  is a huge Cisco USP.

Links for further reading

For more information and data sheets on the C4200 and C125 click here

Rather than me call out the different pros and cons of AMD vs Intel, prices per watt and Thermal Design Power (TDP) stats etc..  AnandTech do a great job of an independent “Apples with Apples” comparison of how the AMD EPYC CPU compares to the Intel Skylake CPU Here.

As always let me know your thoughts in the comments!

Colin