A new ReadyNode profiles ESA-AF-0 has been added to expand VMware vSAN Express Storage Architecture (ESA) use cases further on the low end of hardware requirements. In order for the ESA in vSAN to provide the full performance benefits of NVMe devices, the minimum requirements for host CPU, memory, and networking were much higher than compared with the OSA. While these minimum requirements were reflected appropriately in ESA-specific ReadyNode classifications, it created a relatively high barrier for some of our customers. These were customers who had lower performance requirements and smaller environments, but still wanted to exploit the improved efficiency, lower total cost of ownership (TCO), smaller failure/maintenance domains, and new capabilities (e.g. snapshots, etc.) of ESA. virtually all reasons for going with the OSA have been eliminated. The vSAN ESA should be the defacto standard design for all new installations and hardware refreshes for the edge to the core.
The new ReadyNode profile will help our customers and partners across many use cases, including but not limited to:
- Edge/2-node environments running relatively few VMs that simply had too high of a hardware cost associated with the previous requirements.
- Edge environments that wanted a highly simplified BoM for robust use cases (Minimal hardware components and packaging), but could not be achieved due to previous requirements.
- Smaller commercial or smaller enterprise environments with low to modest workload demands that wish to move to ESA, but did not currently have the backing infrastructure to support it (25/100GbE networking, hosts with high entry cost, etc.)
New Node Sizes
The new vSAN-ESA-AF-0 ReadyNode profile has the following minimum requirements:
- Host CPU: 16 or more cores
- Host Storage devices: 2 or more NVMe storage devices (1.6TB or greater Mixed-Use devices, or 1.92TB or greater Read-Intensive devices)
- Host RAM: 128GB or more
- Host networking: 10GbE or more
- This is 1/2 the CPU as the AF-2, 1/4 the RAM, 1/4 the storage, less than 1/2 the networking bandwidth required per host compared to the ESA-AF-2 profiles.
Drive considerations Minimums and 2-node considerations
While the vSAN-ESA-AF-0 ReadyNode can use as few as two NVMe devices per host, for 2-node environments, it is advised to use at least 3 (4 preferred) so that the customer can use the secondary level of resilience (2+1 RAID-5) capabilities of ESA without the purchase of additional hardware. The use of secondary levels of resilience in a 2-node cluster is a simple and effective way to substantially increase the resilience of data in 2-node environments.
Read Intensive drives have started appearing on the vSAN VCG, and complement this readymade profile in driving down cost per GB by another 20% or more.
10Gbps Networking considerations
Many customers looking for ESA ReadyNodes with 10Gbps support do so because of an existing switch lifecycle. They may have budget and timing to replace a cluster this year, but the switching is not scheduled for refresh until the following year or more. While 10Gbps networking NICs will be supported, many customer should strongly consider purchasing 25Gbps NICs if there is any intention of later upgrading switching. Many 25Gbps switches also have additional value beyond the interface speed (additional CPU offload functions, RDMA support, overlay offload support) that may prove valuable for the nominal uplift in charge. 25Gbps NICs using SFP28 interfaces are commonly backwards compatible with SFP+ 10Gbps optics, cables and transceivers. For 2-node clusters it is still recommended to use faster network interfaces where possible, and use the direct connection option to bypass the need for switches for vSAN/vMotion traffic.
Do vSAN ReadyNodes certified for ESA need to be purchased using a single ReadyNode SKU? No! One can create an emulated ReadyNode configuration using the same hardware and it will be fully supported by VMware. For more information, see the post: “Support for ReadyNode Emulated Configurations in vSAN ESA.”
Scaling down considerations
A reduction in hardware minimums may come with other technical costs to the customer. For example, the lower minimums do not mean that those specifications will be used if the customer wishes to host resource intensive VMs, or the increase in the maximum of VMs supported per host (for the ESA in vSAN 8 U2). Proper use of the vSAN ReadyNode sizer is an important step to sizing an environment correctly.
What can I change? Components of a ESA-AF-0 ReadyNode can be improved/increased in a number of ways. Additional drives, faster NICs, bigger CPUs, and more memory can be added. For a longer blog explaining what can be changed, as well as providing some context for the process see this blog.
vSAN’s new ReadyNode profile and allowance of lower-endurance storage devices make adopting vSAN ESA easier than ever. The introduction of a new, entry-level ReadyNode classification relieves perhaps the single biggest hurdle for new and existing customer’s ability to adopt vSAN ESA. It also is a critical part in helping our customers transition to the ESA while their existing hardware (e.g. 10GbE switching) eventually is replaced by faster networking. The enhancements noted above are targeted for the smaller data center and/or edge environments. virtually all reasons for going with the OSA have been eliminated. The ESA should be the defacto standard design for all new installations and hardware refreshes for the edge to the core.
