راه اندازی SAP بر روی Virtual SAN
This blog is co-authored by my colleague Erik Rieger. Erik is a Global Solutions Architect in SI/SO and ISV technical alliance, specifically SAP.
There is no doubt that Hyper-Converged Infrastructure (HCI) based on VMware Virtual SAN provides a great platform for running Business Critical Applications (BCAs). A recent customer survey found that more than 60% of our customers trust Virtual SAN with the BCAs today, making BCA the most common use case.
We have done extensive technical validation and published a series of reference architecture papers about running Oracle, SQL Server, and Exchange on Virtual SAN. In reality, BCAs deployed by our customers today is not limited to that list and there are plenty more applications that we want to highlight! Let’s tackle one more today: SAP.
So how about SAP applications? Is Virtual SAN a supported platform for SAP? Does Virtual SAN provide sufficient performance for the demanding SAP HANA database? Are there specific hardware requirements?
Let’s get the fundamentals out of the way first. For SAP classic, non-SAP HANA applications, SAP does not require a specific storage certification. For details please refer to SAP note 2273806. As an integral part of the hypervisor, Virtual SAN is embedded in the vSphere kernel. Therefore, SAP treats it as a feature of the supported vSphere hypervisor and as such customers can readily use Virtual SAN in their SAP environments. In other words, Virtual SAN is fully supported for SAP applications, like SAP NetWeaver based products or SAP Business One, in production. For a complete list of currently supported SAP products on vSphere please review SAP notes 1492000 and 2161991. Just one of the many advantages over other bolted-on HCI solutions in our opinion.
Better yet, VMware provides the one-stop support experience to customers running SAP applications on Virtual SAN. To escalate Virtual SAN related issues in these SAP 
environments, simply collect a VMware performance snapshot as described in note 1158363 and vSphere support bundles. Next open a ticket directly with VMware, and we will take it from there! Customers using other HCI solutions in similar situations will have to work with their solution vendors first before proving it is a vSphere related issue and then escalating to VMware. Certainly customers would appreciate the simplest and fastest route to resolution when BCAs are concerned, another advantage of Virtual SAN.
Customers wanting to modernize their existing aged and complex SAP environments, as shown in the figure below, can now consolidate their SAP landscapes on Virtual SAN based HCI solutions running on both VMware and SAP certified x86 servers, to eliminate traditional IT silos of compute, storage, and networking. All intelligence and management moves into a single Hyper-Converged Software (HCS) stack, allowing a VM and application-centric policy-based control and automation. This brings better quality of service, security, higher performance, operational simplicity, and cost-effectiveness into SAP application environments.
Now let us talk about SAP’s In-Memory Database HANA, which is a different beast in itself. Traditional database systems store the majority of data on disk and as such will have VMs with relatively small footprints of 8-128 GB vRAM and 2-16 vCPUs. SAP HANA VMs are in comparison extreme, a HANA VM can easily be configured to reach the vSphere VM maximums of 128 vCPUs or 4 TB of RAM.
SAP HANA Tailored Datacenter Integration (TDI) is a program for allowing customers to leverage existing hardware and infrastructure components for their SAP HANA environment. Currently TDI targets enterprise network and enterprise storage solutions. All of the TDI certified enterprise storage solutions are SAN or NAS arrays today. Virtual SAN represents a totally different architecture, it is a paradigm shift of how storage is architected and consumed by HANA. We are actively working with SAP on this matter to determine how Virtual SAN can be supported.
For testing purposes, we set up a modest 4-node Virtual SAN All Flash (AF) cluster using Dell R630 servers. Each server had 2x E5-2670 2.3GHz processors, 256GB RAM, and two disk groups of 400GB cache tier SSD and 4x 400GB capacity tier SSDs. The SAP HANA HWCCT VMs used the default availability policy of Failures to Tolerate (FTT) of 1. The servers are categorized as entry-level HANA E5 systems by SAP. The test setup is illustrated in the following architecture diagram, there is one HANA HWCCT test VM per node.
We then ran the SAP HANA hardware configuration check tool (HWCCT) in all four VMs concurrently to ensure the SAP HANA TDI KPIs for data throughput and latency are met. The FSPerf results are excellent; every single KPI including 1ms latency has been beat. A small snippet of the average performance data across all 4 VMs follows:
- Log I/O at 16K block size: 601.75 micro seconds latency
- Data I/O at 1M block size: 338.2MB/s initial write throughput, 527.6MB/s overwrite throughput, and 925.9MB/s read throughput
The following Virtual SAN Observer chart illustrates the latency and IOPS history of one host during the (log-16K-latency) test run. Virtual SAN latency was consistently under 1ms, matching what the application was reporting.
The same HWCCT tool was also run on a similarly configured Lenovo M5 test bed, and all KPIs were easily met as well, confirming that Virtual SAN as a software-defined solution is able to satisfy HANA performance requirements and can therefore fulfill the needs of any other SAP applications. This is just a sneak peek into a reference architecture paper we are working on. A lot more will be covered in the paper, so stay tuned.
There are many SAP application production and non-production use cases including test/dev, QE, reporting, etc. where Virtual SAN can already be used. If deployed in SAP landscapes, ensure the servers used are certified and listed in the SAP HANA Product Availability Matrix and Virtual SAN Compatibility Guide. Additionally, you must use storage components, including controller, SSD, firmware and driver that are certified for VMware Virtual SAN either in the form of a Virtual SAN Ready Node configuration or certified components.
To summarize, VMware Virtual SAN is the first step towards simpler and automated storage management through an application-centric approach. Virtual SAN can get used for SAP applications such as SAP Business One, SAP ERP, SAP CRM and other NetWeaver platform based solutions in production environments. Meanwhile, SAP does not support HANA on Virtual SAN or any HCI architecture and solutions today, VMware is working with SAP to jointly determine the best approach to achieve SAP HANA support for Virtual SAN. We will update as soon as we make further progress there. More details including SAPS and IOPS sizing can also be found in the SAP SCN blog on this very topic.