Write Accelerator
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Storage Solutions for SAP on Azure builds on storage topics discussed in Design an Azure Infrastructure for SAP Workloads and Design and Build High Availability and Disaster Recovery for SAP Workloads (coming soon). Data storage needs to be fast, responsive, and secure, but above all, continually available.

This course delves into greater detail on previously discussed topics and introduces new, more complex subject matter and its application to SAP workloads to ensure business continuity.

Learning Objectives

  • Understand the various disk types available in Azure
  • Learn how Azure Shared Managed Disks and Storage Spaces Direct can be used for SAP workloads
  • Learn about scale-out file system
  • Understand what disk striping and disk caching are
  • Learn when and how to enable disk write acceleration and how to encrypt disks with SAP workloads

Intended Audience

This course is designed for anyone looking to explore the Azure storage solutions available for SAP workloads.


To get the most out of this course, you should already have some experience working with SAP and Azure. Before embarking on this course, we recommend you take a look at Design an Azure Infrastructure for SAP Workloads and Design and Build High Availability and Disaster Recovery for SAP Workloads first.


While Azure Premium disks are the minimum recommendation for SAP workloads, even with standard caching configured, they don't meet the latency requirements for SAP HANA. To achieve the required latency, you need to enable write acceleration for /hana/log. HANA data can be stored on premium disks without the Write Accelerator or on Ultra disks. Ultra disks meet the HANA log latency criteria. 

Write acceleration is only available on Azure Premium Managed disks when used in combination with M-Series virtual machines. Enabling the Write Accelerator on a disk will require you to stop processes accessing the disk, or if an OS disk will mean rebooting the VM. Disk caching must be set to none or read-only prior to enabling the write accelerator. As with most Azure resource management, you can configure a disk's write accelerator via the CLI, portal, or Powershell. 

This script snippet adds a new write accelerated disk to an existing VM. Note the Update-AzVM command to enact the configuration change without the need to reboot the machine. Here we have a Powershell script enabling write acceleration on an existing disk. These Azure CLI commands, starting from the top, enable Write Accelerator on an existing disk, attach a Write Accelerator enabled disk, and disable a Write Accelerator. When using the az vm update command, you can specify individual disks with their LUN numbers, or apply the command to all attached disks by omitting the number and just using true or false. Finally, we have a JSON Azure Resource Manager template section setting write Accelerator enabled to true.

About the Author
Learning Paths

Hallam is a software architect with over 20 years experience across a wide range of industries. He began his software career as a  Delphi/Interbase disciple but changed his allegiance to Microsoft with its deep and broad ecosystem. While Hallam has designed and crafted custom software utilizing web, mobile and desktop technologies, good quality reliable data is the key to a successful solution. The challenge of quickly turning data into useful information for digestion by humans and machines has led Hallam to specialize in database design and process automation. Showing customers how leverage new technology to change and improve their business processes is one of the key drivers keeping Hallam coming back to the keyboard.