Two Hot IT Topics Standing Alone, Until Now…
Two of the hottest topics and IT trends right now are hyper-converged infrastructure (HCI) and NVMe Over Fabrics (NVMe-oF). The hotness of HCI is evident in the IPO of Nutanix in September and HPE’s acquisition of Simplivity in January 2017. The interest in NVMe-oF has been astounding with all the major storage vendors working on it and all the major SSD vendors promoting it as well.
But the two trends have been completely separate—you could do one, the other, or both, but not together in the same architecture. HCI solutions could use NVMe SSDs but not NVMe-oF, while NVMe-oF solutions were being deployed either as separate, standalone flash arrays or NVMe flash shelves behind a storage controller. There was no easy way to create a hyper-converged solution using NVMe-oF.
Excelero NVMesh Combines NVMe-oF with HCI
Now a new solution launched by Excelero combines the low latency and high throughput of NVMe-oF with the scale-out and software-defined power of HCI. Excelero does this with a technology called NVMesh that takes commodity server, flash, and networking technology and connects it in a hyper-converged configuration using an enhanced version of the NVMe-oF protocol. With this solution, each node can act both as an application server and as a storage target, making its local flash storage accessible to all the other nodes in the cluster. It also supports a disaggregated flash model so customers have a choice between scale-out converged infrastructure and a traditional centralized storage array.
Figure 1: Excelero NVMesh combines NVMe-oF with HCI, much like combining peanut butter and chocolate into one tasty treat).
Remote Flash Access Without the Usual CPU Penalties
NVMesh creates a virtualized pool of block storage using the NVMe SSDs on each server and leverages a technology called Remote Direct Drive Access (RDDA) to let each node access flash storage remotely. RDDA itself builds on top of industry-standard Remote Direct Memory Access (RDMA) networking to maintain the low latency of NVMe SSDs even when accessed over the network fabric. The virtualized pools allow several NVMe SSDs to be accessed as one logical volume by either local or remote applications.
In a traditional hyper-converged model, the storage sharing consumes some part of the local CPU cycles, meaning they are not available for the application. The faster the storage and the network, the more CPU is required to share the storage. RDDA avoids this by allowing the NVMesh clients to directly access the remote storage without interrupting the target node’s CPU. This means high performance—whether throughput or IOPS—is supported across the cluster without eating up all the CPU cycles.
Recent testing showed a 4-server NVMesh cluster with 8 SSDs per server could support several million 4KB IOPS or over 6.5GB/s (>50Gb/s)—very impressive results for a cluster that size.
Figure 2: NVMesh leverages RDDA and RDMA to allow fast storage sharing with minimal latency and without consuming CPU cycles on the target. The control path passes through the management module and CPUs but the data path does not, eliminating potential performance bottlenecks.
Integrates with Docker and OpenStack
Another feature NVMesh has over the standard NVMe-oF 1.0 protocol is that it supports integration with Docker and OpenStack. NVMesh includes plugins for both Docker Persistent Volumes and Cinder, which makes it easy to support and manage container and OpenStack block storage. In a world where large clouds increasingly use either OpenStack or Docker, this is a critical feature.
Figure 3: Excelero’s NVMesh includes plug-ins for both Docker and OpenStack Cinder, making it easy to use it for both container and cloud block storage.
Another Step Forward in the NVMe-oF Revolution
The launch of Excelero’s NVMesh is an important step forward in the ongoing revolution of NVMe over Fabrics. The open source solution supports high performance but only with a centralized storage solution and without many important storage features. The NVMe-oF array solutions offer a proven appliance solution but some customers want a software-defined storage option built on their favorite server hardware. Excelero offers them all of these features together: hyper-converged infrastructure, NVMe over Fabrics technology, and software-defined storage.