In part 1 we introduced the concept of SAP HANA Application Workload guidance and using example business requirements to come up with a workload and vSphere cluster design for the SAP environment. In part 2 we looked at storage, network and security design for the proposed customer environment. In this part we will look at monitoring & management, backup/recovery and disaster recovery for SAP S4/HANA.
SAP S/4HANA Monitoring and Management
Nearly every component of the IT stack contributes to application performance, which can make it challenging to identify the cause of issues when they arise. For many organizations, a lack of visibility can lead to mean-time-to-innocence hunts that waste time and create alert storms that drain the productivity of business teams. With a complex application such as SAP S/4HANA, performance issues can be even more difficult to specify because the application requires resources from the virtual environment, the network, and databases. However, integrating monitoring into a single console—such as VMware vRealize Operations Manager can provide visibility into SAP workloads and other IT relationships to impact performance.
Choosing the right availability configuration for your SQL Server on vSphere can be a bit confusing as there are more than a few options to choose from, questions such as: Should I use vSphere HA if i’m using AlwaysOn? What are the implications of running different availability configurations on vSphere, and what are the best practices?
This very popular guide called “Microsoft SQL Server on VMware vSphere Availability and Recovery Options” which outlines the availability options and best practices for SQL Server on vSphere and tries to answer these question, is now updated with the latest information.
Microsoft SQL server is the most virtualized enterprise mission critical application today. In recent years it has become a mainstream effort among VMware customers to virtualize critical databases to allow better agility and scale while increasing availability and operational efficiency.
This guide, now named “Architecting Microsoft SQL Server on VMware vSphere – Best Practices Guide” to reflect its focus on architecture and configurations of vSphere as well as SQL server for maximizing the benefits of virtualizing SQL server, is aimed at providing VMware customers and partners guidance on how to achieve best performance and efficiency with the latest versions of Microsoft SQL server and VMware vSphere.
In this guide there are also references to other VMware and third-party documents which we encourage the reader to consult for better understanding of the topics discussed.
Starting with update releases in December, 2014, VMware vSphere will default to a new configuration for the Transparent Page Sharing (TPS) feature. Unlike in prior versions of vSphere up to that point, TPS will be DISABLED by default. TPS will continued to be disabled for all future versions of vSphere.
In the interim, VMware has released a Patch for vSphere 5.5 which changes the behavior of (and provides additional configuration options for) TPS. Similar patches will also be released for prior versions at a later date.
Why are we doing this?
In a nutshell, independent research indicates that TPS can be abused to gain unauthorized access to data under certain highly controlled conditions. In line with its “secure by default” security posture, VMware has opted to change the default behavior of TPS and provide customers with a configurable option for selectively and more securely enabling TPS in their environment. Please read “Security considerations and disallowing inter-Virtual Machine Transparent Page Sharing (2080735)” for more detailed discussion of the security issues and VMware’s response. Continue reading →
What’s the CPU Utilization Of Standalone SAP Central Services in a Virtual Machine?
Since VMware came out with VMware Fault Tolerance (FT) we have considered the deployment option of installing SAP Central Services in a 1 x vCPU virtual machine protected by VMware FT. FT creates a live shadow instance of a virtual machine that is always up-to-date with the primary virtual machine. In the event of a hardware outage, VMware FT automatically triggers failover—ensuring zero downtime and preventing data loss. Central Services is a single-point-of-failure in the SAP architecture that manages transaction locking and messaging across the SAP system and failure of this service results in downtime for the whole system. Hence Central Services is a strong candidate for FT but FT currently only supports 1 x vCPU (vSphere 5.x), so some guidance is required on how many users we can support in this configuration. VMware has given technical previews of multi-vCPU virtual machines protected by FT at VMworld 2013/2014, but now, better late than never, here are the results of a lab test demonstrating the performance of standalone Central Services in a 1 x vCPU virtual machine. Continue reading →
Availability of the applications is one of the important requirements for business critical applications. The vSphere platform provides capabilities to protect against hardware and software failures to meet the stringent SLA requirements of business critical applications.
Virtualized applications can avail of features such as vSphere HA protects from HW failures by restarting virtual machines on surviving hosts if a physical host were to fail. vSphere FT (Fault Tolerance) protects critical servers such as load balancers and other central servers with a small footprint (1vCPU) with zero downtime in the event of HW failures.
vSphere App HA for Application level protection for supported applications. Third party solutions that leverage vSphere Application Awareness API such as Symantec Application HA , NEVERFAIL, etc. layer on top of VMware HA and provide monitoring and availability for most of the common business critical applications.
The type of licensing impacts the cluster design for SAP virtualization. SAP is supported on most common database platforms such as SQL, Oracle, DB2 and SYBASE. When customers procure SAP, they can choose to buy the database licensing through SAP or purchase it directly from the database vendor. This decision impacts the cluster design for virtualized SAP environments.
Let us look at these two scenarios and their impact on the design.
Scenario 1: Database License procured from the DB vendor for SAP:
Database vendors have differing but usually very restrictive policies regarding virtual machines running databases. The cost of licensing databases in the extreme case could force a customer to license for the entire cluster, even though the database could be using only a small subset of the resources. Due to the uncertainty and the risk involved with DB licensing in this situation, it might be prudent to separate the entire database workload into its own cluster. By separating the entire database workload, the physical hardware used for databases can be isolated and licensed fully. Since only database workloads exist in this cluster one can achieve consolidation and efficiency for databases. The main disadvantage is the added overhead of having a separate cluster for databases. Since SAP landscapes have many modules with each module having its own individual database, creating a separate DB cluster with a good number of hosts is worthwhile and justified. Continue reading →
Over the past few years, there has been significant acceleration in adoption of the VMware platform for virtualization of business critical applications. When vSphere 5 was introduced with its initial support for up to 32 vCPU many of the vertical scalability concerns that existed earlier were addressed. This has been increased to 64 processors with the later vSphere 5.x releases ensuring that more than 99% of all workloads will fit vertically.
Having personally worked in IT infrastructure for more than 20 years with a strong focus on implementing and managing business critical applications, I see a general reluctance from application owners to virtualize business critical applications. When virtualizing business applications there are many critical factors one should consider. I seek to address the typical concerns of application owners about Virtualization with this multipart series on Virtualizing BCA. Continue reading →