The announcement of vSAN Max™ marked a significant milestone for VMware and its customers. The ability to provide dedicated, scale-out storage for vSphere clusters using nothing more than commodity servers and VMware’s hypervisor, opens new doors for customers and partners alike. Whether it be the flexible options in design, the management interface they already know (vCenter Server), or the cost-effective and incremental scalability in performance and capacity, vSAN Max is gaining a lot of attention.
To support this introduction, the vSAN ReadyNode™ program has been updated to accommodate cluster configurations using vSAN Max. Let’s look at the options, and how they may fit in your environment.
Multiple vSAN ReadyNode Profiles Certified for vSAN Max
The vSAN ReadyNode program was designed to provide server configurations using hardware certified for vSAN HCI clusters. Paired with the vSAN ReadyNode sizer, It offers a simple, customizable way for customers to build out cluster configurations that meet specific needs.
A vSAN Max cluster may be expected to serve multiple Petabytes of storage to dozens of hosts that may demand millions of IOPS. We want to ensure that the hosts that make up a vSAN Max cluster are using hardware capable of meeting the needs of our customers. As shown in Figure 1, the vSAN ReadyNode program now includes four new ReadyNode profiles specifically designed for use in vSAN Max clusters.
Figure 1. ReadyNode profiles certified for vSAN Max.
Each ReadyNode profile for vSAN Max aims to address a desired level of capacity and performance. A vSAN-Max-Med profile will provide higher capacity and performance than a vSAN-Max-SM, which provides more capacity and performance than a vSAN-Max-XS profile. ReadyNodes certified for vSAN Max can be procured through your favorite server vendor using their single SKU, or through a ReadyNode emulated configuration, where a ReadyNode is built using certified components from an approved ReadyNode vendor.
Much like ReadyNodes certified for vSAN HCI clusters, ReadyNodes certified for vSAN Max have been configured to offer a balanced, proportionate amount of hardware resources across various resource types, such as CPU, RAM, storage devices, and NICs. Why is this important? A balanced server configuration helps prevent stranded resources due to one aspect of the configuration, such as CPU, network, etc. being dramatically undersized. It also improves utilization of existing resources, which ultimately drives down costs, and delivers better performance consistency. Customers also have flexibility in how many hosts they can have in a vSAN Max cluster. For more information on cluster host counts, see the vSAN ReadyNode Host Specifications and Sizing section, as well as the Cluster Design and Sizing section of the “vSAN Max Design and Operational Guidance” document.
Note that the ReadyNodes listed above apply only to the vSAN Max cluster. vSphere clusters mounting the datastore can use any hardware so long as it is on the VMware compatibility guide for vSphere.
Configuration Minimums
Some of the configuration minimums deserve additional explanation and are noted below.
- Host capacity. The stated host capacity listed in the table is achieved by a minimum of 8 storage devices in a host. This helps ensure that sufficient NVMe resources are available for I/O processing.
- Storage devices. The NVMe-based TLC storage devices of up to 15.3TB are certified for vSAN. For maximum convenience and value, vSAN Max hosts can use higher endurance “mixed-used” storage devices, or lower endurance “Read-Intensive” storage devices. As with ReadyNodes for vSAN HCI clusters, devices with different endurance ratings cannot be mixed in a single host or across a vSAN Max cluster.
- Network bandwidth. The stated network minimum of a ReadyNode for vSAN Max refers to the minimum physical uplink speed required, and is the minimum required. More networking resources are always preferred to help minimize the potential of network contention. Just as with vSphere clusters and vSAN HCI clusters, hosts should have more than one uplink for redundancy. A simple Active/Standby configuration can be used, or aggregating two links using LACP can be used if the environment supports it. vSAN Max, which is built using the ESA, also supports the use of multiple VMkernel ports when they are configured on different subnets. This will use the VMkernel ports in a in a round-robin fashion to deliver higher throughput than a single uplink, without the operational challenges of a LAG. More information on network configuration options will be forthcoming.
- CPU core counts and RAM. You might wonder why CPU core counts and RAM on the higher-end ReadyNode profiles for vSAN Max are as high as they are. The reason is consistent with why higher-end ReadyNode profiles require faster networking. To exploit the full capabilities of the higher-end ReadyNodes that are comprised of up to 24 high-density storage devices, one needs sufficient CPU cores, RAM, and networking bandwidth to deliver the highest levels of performance of those devices under maximum load. Lower-end ReadyNode profiles for vSAN Max have lower capacities with fewer storage devices and can achieve the highest levels of performance of those devices with less supporting hardware.
The ReadyNode profiles listed in the table generally refer to hardware minimums. The hardware resource types such as storage devices, CPU, RAM, and networking in each ReadyNode profile could conceivably be changed to an amount much larger than the minimum. But depending on the amount that one type of a resource, such as storage devices is increased, one may no longer have sufficient compute, memory, or network resources to exploit the full potential of the adjusted capacity.
Recommendation: If you want to increase one resource type substantially (equal to or greater than the next higher profile) from a vSAN Max ReadyNode profile, consider looking at the next higher ReadyNode profile available. This will help keep your server resources proportional and deliver better performance and resource utilization. Selecting the next higher ReadyNode profile available will also allow the cluster to more easily accommodate higher-demanding workloads in the future.
For more information and recommendations on designing a vSAN Max cluster, see: “vSAN Max Design and Operation Guidance.”
Summary
Much like ReadyNodes for vSAN HCI clusters, the ReadyNodes available for vSAN Max are designed to make the process of sizing server configurations using certified hardware easy and predictable. These four ReadyNode profiles will address the needs of your organization, regardless of capacity and performance requirements.
