Disclaimer: I recently attended VMworld 2017 – US. My flights were paid for by ActualTech Media, VMware provided me with a free pass to the conference and various bits of swag, and Tech Field Day picked up my hotel costs. There is no requirement for me to blog about any of the content presented and I am not compensated in any way for my time at the event. Some materials presented were discussed under NDA and don’t form part of my blog posts, but could influence future discussions.
What’s In A Name?
There’s been some amount of debate about whether NetApp’s HCI offering is really HCI or CI. I’m not going to pick sides in this argument. I appreciate that words mean things and definitions are important, but I’d like to focus more on what NetApp’s offering delivers, rather than whether someone in Tech Marketing made the right decision to call this HCI. Let’s just say they’re closer to HCI than WD is to cloud.
Ye Olde Architectures (The HCI Tax)
NetApp spent some time talking about the “HCI Tax” – the overhead of providing various data services with first generation HCI appliances. Gabe touched on the impact of running various iterations of controller VMs, along with the increased memory requirements for services such as deduplication, erasure coding, compression, and encryption. The model for first generation HCI is simple – grow your storage and compute in lockstep as your performance requirements increase. The great thing with this approach is that you can start small and grow your environment as required. The problem with this approach is that you may only need to grow your storage, or you may only need to grow your compute requirement, but not necessarily both. Granted, a number of HCI vendors now offer storage-only nodes to accommodate this requirement, but NetApp don’t think the approach is as polished as it could be. The requirement to add compute as you add storage can also have a financial impact in terms of the money you’ll spend in licensing for CPUs. Whilst one size fits all has its benefits for linear workloads, this approach still has some problems.
The New Style?
NetApp suggest that their solution offers the ability to “scale on your terms”. With this you can
- Optimise and protect existing investments;
- Scale storage and compute together or independently; and
- Eliminate the “HCI Tax”.
Note that only the storage nodes have disks, the compute nodes get blanks. The disks are on the front of the unit and the nodes are stateless. You can’t have different tiers of storage nodes as it’s all one cluster. It’s also BYO switch for connectivity, supporting 10/25Gbps. In terms of scalability, from a storage perspective you can scale as much as SolidFire can nowadays (around 100 nodes), and your compute nodes are limited by vSphere’s maximum configuration.
There are “T-shirt sizes” for implementation, and you can start small with as little as two blocks (2 compute nodes and 4 storage nodes). I don’t believe you mix t-shirt sizes in the same cluster. Makes sense if you think about it for more than a second.
Converged and hyper-converged are different things, and I think this post from Nick Howell (in the context of Cohesity as HCI) sums up the differences nicely. However, what was interesting for me during this presentation wasn’t whether or not this qualifies as HCI or not. Rather, it was about NetApp building on the strengths of SolidFire’s storage offering (guaranteed performance with QoS and good scale) coupled with storage / compute independence to provide customers with a solution that seems to tick a lot of boxes for the discerning punter.
Unless you’ve been living under a rock for the last few years, you’ll know that NetApp are quite a different beast to the company first founded 25 years ago. The great thing about them (and the other major vendors) entering the already crowded HCI market is that they offer choices that extend beyond the HCI play. For the next few years at least, there are going to be workloads that just may not go so well with HCI. If you’re already a fan of NetApp, chances are they’ll have an alternative solution that will allow you to leverage their capability and still get the outcome you need. Gabe made the excellent point that “[y]ou can’t go from traditional to cloud overnight, you need to evaluate your apps to see where they fit”. This is exactly the same with HCI. I’m looking forward to see how they go against the more established HCI vendors in the marketplace, and whether the market responds positively to some of the approaches they’ve taken with the solution.