At VMworld, various cool new technologies were previewed. In this series of articles, I will write about some of those previewed technologies. Unfortunately, I can’t cover them all as there are simply too many. This article is about VMware Cluster Memory, which was session OCTO2746BU. For those who want to see the session, you can find it here. I first learned about VMware Cluster Memory at our VMware internal R&D conference in May this year, and immediately got excited about it. Please note that this is a summary of a session which is discussing a Technical Preview, this feature/product may never be released, and this preview does not represent a commitment of any kind, and this feature (or it’s functionality) is subject to change. Now let’s dive into it, what is Cluster Memory?
Well, it is exactly what you would expect it to be. Providing the ability to create a pool of cross-host memory resources. Now in order to do this, the first problem that needs to be looked at is the network. As mentioned in the session, the ratio of network to memory latency has lowered significantly. In 1997 the ratio was 1000 roughly, right now it is below 10. Meaning that network latency has lowered from milliseconds to low microseconds. Today to reach these low microseconds latencies technologies like RDMA will need to be considered. This change is very important for the Cluster Memory feature being discussed. Also very important, is the fact that RDMA is affordable, and this means it will be coming to a data center near you soon. A huge difference compared to years ago.