With SSD, RAM, and flash prices falling but storage vendors maintaining their margins on array hardware there is an increasing niche for flash-based caching solutions. These solutions promise better performance at lower costs than retrofitting your legacy arrays and are becoming quite a market, especially for virtualization infrastructure. Infinio is one startup that is competing in this space.
Infinio describes their Accelerator product as “a software-only NAS offload engine.” From the IT staff perspective it is a management interface that installs virtual appliances into VMware vSphere environments, intercepting the flow of NFS traffic (and only NFS traffic) to NAS devices. By doing this they can add a local cache and speed disk accesses. They claim that their product works without any additional hardware. That is true, to a point. Unlike some of their competition their cache is RAM-based, using 8 GB per host to do its work, and no SSD is necessary. The virtual appliance that runs on each ESXi host needs to be on local storage, though, so all those diskless ESXi blades you’ve got will need some retrofitting. Furthermore, if you’re using VMware vSphere Autodeploy or SAN booting your ESXi hosts you might need to do some design work in your environment. Infinio says that if this is the case they have some options for you, but it’ll require a support call.
You might want to do that design work, though, because Infinio can actually take advantage of SSDs installed on hosts. The SSDs don’t need to be in every host, as the Accelerators talk to each other across the vSphere management network interfaces. This way they can share cache data and avoid disk accesses at the cluster level. It also likely foreshadows a future ability to do write caching. Right now the Infinio Accelerator is a read-only cache. Read-only caches are easier to implement and don’t cause problems with array-based snapshots, replication, volume consistency, reliability, etc. The typical claim is also that by removing read traffic from the SAN you’re freeing it up to handle writes. That’s true, but write caching is a nice feature, and one that sets competitors like PernixData FVP apart. While both Infinio and PernixData consider each other to be serious competition, as of this writing they are actually not. PernixData FVP only caches block-level storage traffic, and Infinio only caches NFS traffic.
The Infinio Accelerator uses 8 GB of RAM for cache, and two vCPUs. I’ve written before about considerations to make when using virtual appliances to provide storage services, and this solution is no different. The resources that are consumed by these appliances need to be 100% committed to them, which means that you are losing two CPU cores and 8 GB of RAM per host to this solution. That is a form of opportunity cost – in a cloud provider environment the loss of revenue from those two cores, per host, should be compared to the price of acquiring native SSD or flash for the array itself. The same is true of VDI, where implementations often get high VM-to-CPU ratios. Truly busy environments also might not be suitable for virtual appliance-based storage, either. You don’t want your workloads competing with their storage for CPU and memory.
The Accelerator management interface is delivered as a separate virtual appliance, and has a simple, easy-to-use, well-thought-out UI for deploying and managing the environment. Infinio Accelerator can install and remove itself from your I/O stream seamlessly, which is a nice feature. Very few vendors allow for proper trials, and the ones that do usually are not focused on removal. After all, shouldn’t you just buy the product and leave it installed? By offering an exit strategy Infinio is removing a lot of the risk from trying their product. Download it from their web site without having to talk to a sales droid, install it, see how well it works with your actual workloads for 30 days, and then remove it quickly if you decide it isn’t for you. Absolutely wonderful. Another aspect where this works well is software upgrades, too. If the Accelerator can seamlessly install and remove itself that makes for a great in-place product maintenance strategy.
The Infinio Accelerator is in beta right now, but will be shipping in Q4 2013. You can download the beta directly from the web site, and the final product will be available in the same way. Definitely worth a look if you have NFS storage.