I had the opportunity to speak to Jason Collier and Alan Conboy from Scale Computing about a month ago after they announced their “single-node configuration of its HC3 virtualization platform”. This is “designed to deliver affordable, flexible hyperconverged infrastructure for distributed enterprise and Disaster Recovery (DR) use cases”. I’m a big fan of Scale’s HC3 platform (and not just because they gave me a HC1000 demo cluster to trial). It’s simple, it’s cheap, and it works well for its target market. Traditionally (!), HCI and other converged offerings have called for 3 nodes (and sometimes 2) to be considered resilient at a cluster level. When Scale sell you their HC3 solution you start at 3 nodes and work up from there. So how do they do the single-node thing?
In the market I operate in, the use of a single node at the edge makes quite a bit of sense. Customers with edge sites generally don’t have access to IT resources or even suitable facilities but they sometimes have a reasonable link back to the core or decent WAN optimisation in place. So why not use the core to provide the resiliency you would have normally configured locally? Scale call this the “distributed enterprise” model, with the single node HC3 solution replicating workload back to the core. If something goes wrong at the edge you can point users to your workload in the core and keep on going [do you like how I made that sound really simple?].
You can also use the single-node configuration as a DR target for an HC3 cluster. The built-in replication can be configured quickly and without extra software to a single HC3 node located locally or remotely. This, again, is a cheap and cheerful solution to what can sometimes be seen as an expensive insurance policy against infrastructure failure.
Thoughts and Further Reading
Risk versus cost is a funny thing. Some people are very good at identifying risk but not very good at understanding what it will cost them if something goes wrong. Some people like to talk a lot about risk but then their only mitigation is to note it in a “risk register”. In any case, I think Scale have come up with a smart solution because they’re selling to people in a cost sensitive market. This solution helps to alleviate some of the expense related to providing DR and distribute compute (and thus provides some reduced risk for SMBs). That said, everyone’s situation is different, and you need to assess the risk related to running workload at the edge on a single node. If that node fails, you can failover your workload to the core. Assuming you have a process in place for this. And applications that support it. And sufficient bandwidth from the core to the edge. In any case, if you’re in the market for low-cost HCI, Scale should be on your radar. And if you’re looking at distributed HCI you should definitely be looking at the single-node solution. You can read some more in Scale’s press release here. The solution brief can be found here. El Reg also has something to say about it here. Some generally very useful technical resources from Scale can be found here.