IBM Db2 Azure Virtual Machines DBMS deployment for SAP workload

• 04/10/2019
• 6 minutes to read
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With Microsoft Azure, you can migrate your existing SAP application running on IBM Db2 for Linux, UNIX, and Windows (LUW) to Azure virtual machines. With SAP on IBM Db2 for LUW, administrators and developers can still use the same development and administration tools, which are available on-premises. General information about running SAP Business Suite on IBM Db2 for LUW can be found in the SAP Community Network (SCN) at https://www.sap.com/community/topic/db2-for-linux-unix-and-windows.html.

For more information and updates about SAP on Db2 for LUW on Azure, see SAP Note 2233094.

The are various articles on SAP workload on Azure released. It is recommended to start in SAP workload on Azure - Get Started and then pick the area of interests

The following SAP Notes are related to SAP on Azure regarding the area covered in this document:

As a pr-read to this document, you should have read the document Considerations for Azure Virtual Machines DBMS deployment for SAP workload as well as other guides in the SAP workload on Azure documentation.

IBM Db2 for Linux, UNIX, and Windows Version Support

SAP on IBM Db2 for LUW on Microsoft Azure Virtual Machine Services is supported as of Db2 version 10.5.

For information about supported SAP products and Azure VM types, refer to SAP Note 1928533.

IBM Db2 for Linux, UNIX, and Windows Configuration Guidelines for SAP Installations in Azure VMs

Storage Configuration

All database files must be stored on the NTFS file system based on directly attached disks. These disks are mounted to the Azure VM and are based in Azure Page BLOB Storage (https://docs.microsoft.com/rest/api/storageservices/Understanding-Block-Blobs--Append-Blobs--and-Page-Blobs) or Managed Disks (https://docs.microsoft.com/azure/storage/storage-managed-disks-overview). Any kind of network drives or remote shares like the following Azure file services are NOT supported for database files:

• https://blogs.msdn.com/b/windowsazurestorage/archive/2014/05/12/introducing-microsoft-azure-file-service.aspx
• https://blogs.msdn.com/b/windowsazurestorage/archive/2014/05/27/persisting-connections-to-microsoft-azure-files.aspx

Using disks based on Azure Page BLOB Storage or Managed Disks, the statements made in Considerations for Azure Virtual Machines DBMS deployment for SAP workload apply to deployments with the Db2 DBMS as well.

As explained earlier in the general part of the document, quotas on IOPS throughput for Azure disks exist. The exact quotas are depending on the VM type used. A list of VM types with their quotas can be found here (Linux) and here (Windows).

As long as the current IOPS quota per disk is sufficient, it is possible to store all the database files on one single mounted disk. Whereas you always should separate the data files and transaction log files on different disks/VHDs.

For performance considerations, also refer to chapter 'Data Safety and Performance Considerations for Database Directories' in SAP installation guides.

Alternatively, you can use Windows Storage Pools (only available in Windows Server 2012 and higher) as described Considerations for Azure Virtual Machines DBMS deployment for SAP workload to create one large logical device over multiple disks.

For the disks containing the Db2 storage paths for your sapdata and saptmp directories, you must specify a physical disk sector size of 512 KB. When using Windows Storage Pools, you must create the storage pools manually via command line interface using the parameter -LogicalSectorSizeDefault. For more information, see https://technet.microsoft.com/itpro/powershell/windows/storage/new-storagepool.

For Azure M-Series VM, the latency writing into the transaction logs can be reduced by factors, compared to Azure Premium Storage performance, when using Azure Write Accelerator. Hence, you should deploy Azure Write Accelerator for the VHD(s) that form the volume for the Db2 transaction logs. Details can be read in the document Write Accelerator.

Backup/Restore

The backup/restore functionality for IBM Db2 for LUW is supported in the same way as on standard Windows Server Operating Systems and Hyper-V.

You must make sure that you have a valid database backup strategy in place.

As in bare-metal deployments, backup/restore performance depends on how many volumes can be read in parallel and what the throughput of those volumes might be. In addition, the CPU consumption used by backup compression may play a significant role on VMs with up to eight CPU threads. Therefore, one can assume:

• The fewer the number of disks used to store the database devices, the smaller the overall throughput in reading
• The smaller the number of CPU threads in the VM, the more severe the impact of backup compression
• The fewer targets (Stripe Directories, disks) to write the backup to, the lower the throughput

To increase the number of targets to write to, two options can be used/combined depending on your needs:

• Striping the backup target volume over multiple disks in order to improve the IOPS throughput on that striped volume
• Using more than one target directory to write the backup to

High Availability and Disaster Recovery

Microsoft Cluster Server (MSCS) is not supported.

Db2 high availability disaster recovery (HADR) is supported. If the virtual machines of the HA configuration have working name resolution, the setup in Azure does not differ from any setup that is done on-premises. It is not recommended to rely on IP resolution only.

Do not use Geo-Replication for the storage accounts that store the database disks. For more information, refer to the document Considerations for Azure Virtual Machines DBMS deployment for SAP workload.

Accelerated Networking

For Db2 deployments on Windows, it is highly recommended to use the Azure functionality of Accelerated Networking as described in the document Azure Accelerated Networking. Also consider recommendations made in Considerations for Azure Virtual Machines DBMS deployment for SAP workload.

Specifics for Linux deployments

As long as the current IOPS quota per disk is sufficient, it is possible to store all the database files on one single disk. Whereas you always should separate the data files and transaction log files on different disks/VHDs.

Alternatively, if the IOPS or I/O throughput of a single Azure VHD is not sufficient, you can use LVM (Logical Volume Manager) or MDADM as described in the document Considerations for Azure Virtual Machines DBMS deployment for SAP workload to create one large logical device over multiple disks. For the disks containing the Db2 storage paths for your sapdata and saptmp directories, you must specify a physical disk sector size of 512 KB.

Other

All other general areas like Azure Availability Sets or SAP monitoring apply as described in the document Considerations for Azure Virtual Machines DBMS deployment for SAP workload for deployments of VMs with the IBM Database as well.