Windows Server 2019 brings about significant improvements across the platform when it comes to software-defined solutions. Software-defined storage is garnering a lot of attention from customers as most are looking outside of traditional storage with upcoming refreshes for storage infrastructure. With Storage Spaces Direct being introduced in Windows Server 2016, the technology from a Windows perspective is relatively new. However, with Windows Server 2019, Storage Spaces Direct has matured from a new technology to a tried and proven platform for running production workloads.
Table of Contents
- Windows Server 2019 Storage Spaces Direct Best Practices
- Use RDMA
- Use Switch Embedded Teaming
- Resiliency Considerations
- Storage Devices
- Sizing Best Practices
- Buy WSSD Solutions
- Manage Storage Spaces Direct with Windows Admin Center
- Concluding Thoughts
While Windows Server 2019 has only been released for a few days now, there are Windows Server 2019 Storage Spaces Direct Best Practices to note for running S2D on Microsoft’s newest server operating system platform. Many of these best practices carry over from Windows Server 2016 and are worth noting for Windows Server 2019 Storage Spaces Direct.
Windows Server 2019 Storage Spaces Direct Best Practices
When thinking about the various best practices with Storage Spaces Direct in Windows Server 2019, there are several areas we want to consider when thinking about an S2D design. Recently, at Microsoft Ignite, (7) Windows Server 2019 Storage Spaces Direct best practices were considered.
- Using RDMA
- Switch Embedded Teaming
- Resiliency
- Use Storage devices with high endurance
- Size the environment correctly
- Buy WSSD Solutions
- Manage S2D with Windows Admin Center
Let’s take a look at each of these areas and how each contributes to running a Windows Server 2019 Storage Spaces Direct environment that is resilient, stable and performs extremely well.
Use RDMA
RDMA is a core technology to having a Windows Server 2019 Storage Spaces Direct infrastructure that performs really well.
What is RDMA?
RDMA or remote direct memory access allows devices to access memory without having to interact with the operating system. This allows a great deal more performance that devices do have to interact with host operating systems. With RDMA applications have direct access to the network which reduces latency and CPU overhead.
There are basically two methods for implemented RDMA network technology. This can be done using either RoCE or iWarp technology.
RoCE is the most difficult out of the two to configure correctly. However, either can be used to provide a stable and high-performance RDMA network fabric for Storage Spaces Direct.
A few things to consider with RoCE implementations:
- Do not route RoCE traffic
- Do not neglect the switch configuration
With iWarp, the implementation is generally easier than with RoCE. However, there are still things to consider when implementing it with S2D.
- Do not route iWarp traffic
- With high bandwidth implementations, use priority flow control or PFC
Use Switch Embedded Teaming
What is Switch Embedded Teaming or SET?
SET is an alternative NIC teaming solution that can be used in Hyper-V environments with both Windows Server 2016 and Windows Server 2019 that integrates some of the NIC teaming functionality into the Hyper-V virtual switch. This allows grouping between one and eight physical Ethernet network adapters into one or more software-based virtual network adapters.
You can still use the LBFO NIC teaming in the traditional sense, however, using SET allows you to benefit from new switch features such as vRSS, vRDMA, DVMMQ, and RSC. When configuring the network for SMB traffic, use separate subnets for each SMB network. This helps with clear network design and congestion control.
Resiliency Considerations
With Windows Server 2019 Storage Spaces Direct, you have access to many different resiliency options. You can use the following:
- 3-way mirror – three copies of the same block on three different servers. Two servers can fail if you have 4 or more nodes and you will have great performance across the board
- Mirror Accelerated Parity – Mirror accelerated parity is a great compromise of resiliency and capacity. Part of the volume is a three-way mirror, and the other part is double parity so you get the best of both worlds
- Double Parity – This is not recommended and is recommended to use mirror accelerated parity
- 2-way mirror – This is not a recommended configuration unless you are running a two-node cluster
Storage Devices
When sourcing and provisioning cache devices pay attention to the endurance of the cache device. Steer towards cache devices only that have at least 3 DWPD or disk writes per day. With Capacity devices, use devices that have a rating of 1-3 DWPD. With Storage Spaces Direct, you want to have a minimum of (2) cache devices and pay attention to the 4K random I/O numbers of the device in particular.
When considering hardware for caching devices, choose NVMe when possible. NVMe devices are only 30% more expensive but perform 300% faster than comparable SSDs.
Sizing Best Practices
When thinking about the sizing best practices for Storage Spaces Direct, to enable the parallel rebuild feature you need at least one HDD worth of space free in your S2D pool. With the parallel rebuild, the Storage Pool will repair itself even if the failed drive isn’t replaced. Parallel rebuild is much faster than rebuilding the failed drive itself since parallel rebuild is using multiple drives to repair the storage pool instead of rebuilding the single failed drive which can take some time depending on the size and type of the drive.
Be sure to size storage tiers correctly. Set aside at least 10% of your storage pool for caching devices. Provision 20% for the performance tier and the rest for capacity. This will provide a great mix of cache, performance, and capacity for production workloads.
Buy WSSD Solutions
Microsoft has introduced a program called the WSSD Solutions program which stands for “Windows Server Software Defined”. This is essentially a Microsoft certificate for hardware that verifies the hardware is tested and certified to run Storage Spaces Direct. Microsoft sends vendors a rigorous testing program that simulates S2D traffic for a year in the span of a week or so. If the vendor hardware passes the simulated checks, they can become WSSD certified.
Buying these solutions means that you are buying hardware that is certified to run Storage Spaces Direct. This is extremely important from a support perspective and from a stability and reliability perspective for running production workloads.
Manage Storage Spaces Direct with Windows Admin Center
Windows Admin Center is the centerpiece to managing Windows Server 2019. It provides the way forward for managing software defined infrastructure with Windows Server 2019. The Windows Admin Center is a free download from Microsoft if you have a valid Windows operating system license. New dashboards have been designed with Windows Admin Center that allow a high level of visibility into the S2D infrastructure, including historical performance metrics and even health of the infrastructure down to the drive level. Windows Admin Center provides all tools in a single interface instead of having to switch between various tools to manage hosts, clusters, and HCI environments. It is also web based which allows accessing it from any client or server if configured in the gateway mode.
Concluding Thoughts
Windows Server 2019 Storage Spaces Direct provides a powerful platform for running production workloads on top of a software defined infrastructure based on Windows Server Failover Cluster technology. By following best practices with the solution, customers can expect to have the best experience with the platform including stability, performance, and reliability. Many of the recommended best practices carry over from Windows Server 2016 S2D and equally apply with Windows Server 2019. The Windows Sever 2019 S2D best practices cover all areas of the components, including network, virtual switch, sizing, resiliency, certified hardware and others. When provisioning a new Windows Server 2019 Storage Spaces Direct cluster, be sure to follow Microsoft’s recommended best practices for S2D which will ensure the best experience with the latest S2D release.
