Two Main Scale-Up Server Architectures – Part 2

So in my previous article we have discussed about the ‘glueless’ architecture. You may want to read part 1 before proceeding.

We have seen that ‘glueless’ architecture as some serious drawbacks. Let’s see if the second main scale-up server architecture can mitigate those issues. Meet…

The ‘glued’ architecture

We’ve seen that the ‘glueless’ architecture, coordination and communication between the processor sockets, creates a bottleneck. To overcome this problem hardware manufacturers have developed a ‘glue’ to the architecture. This ‘glued’ architecture uses external node-controllers to interconnect QPI island, that is kind of clusters of processor sockets.

Glued Architecture

Glued Architecture

Intel QPI links offers a scalable solutions based on OEM-developed eXternal Node-Controllers (referred to as XNC).  External node-controllers using the Intel Xeon E7-4800 series with embedded memory controller implies a Cache Coherent Non-Uniform Memory Access (ccNUMA) system. The role of ccNUMA is to ensure cache coherency by tracking the most up to date data is for every cache line held in a processor cache.

Latency between processor and memory in a ccNUMA system varies depending on the location of these two components in relation to each other. Manufacturers also want to minimize the bandwidth consumption resulting from the coherency snoop (Intel QPI source broadcast snoopy).

Therefore the quality of the OEM-developed eXternal Node-Controllers is critical and only a few manufacturers are able to provide server architecture which scale in pace with resources added to the system.

The next article in this series, I will focus on Bull’s eXternal Node-Controller called the BCS. Stay tuned!

Source: Bull, Intel, Wikipedia


About PiroNet

Didier Pironet is an independent blogger and freelancer with +15 years of IT industry experience. Didier is also a former VMware inc. employee where he specialised in Datacenter and Cloud Infrastructure products as well as Infrastructure, Operations and IT Business Management products. Didier is passionate about technologies and he is found to be a creative and a visionary thinker, expressing with passion and excitement, hopefully inspiring and enrolling people to innovation and change.
This entry was posted in Bull, Performance and tagged , , . Bookmark the permalink.

2 Responses to Two Main Scale-Up Server Architectures – Part 2

  1. Pingback: Bull’s Implementation of a Glued Architecture « DeinosCloud

  2. Pingback: Bull’s BCS Architecture – Deep Dive – Part 1 « DeinosCloud

Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google+ photo

You are commenting using your Google+ account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )


Connecting to %s