Azure VM Security Considerations

 


Azure VM Security 

If you want to encrypt Azure VM disks, you can use Azure Disk Encryption which uses the BitLocker feature of Windows and DM-Script for Linux to provide volume encryption for the operating system as well as data disks. This solution also works with Azure Key Vault which in turn helps you to control as well as manage the disk encryption keys and secrets. However, it is recommended to use SAP HANA native encryption technology for SAP HANA data-at-rest encryption. 

Note- You should not use the HANA data-at-rest encryption with Azure Disk encryption on the same server, instead use only HANA data encryption for HANA.

SQL Server Transparent Data Encryption (TDE)

The SQL server TDE functionality is fully supported by SAP.

Applying SQL Server TDE

If you want to perform a heterogeneous migration from another DBMS, running on-premise, to Windows/SQL Server running in Azure, you can create your empty target database in SQL server before time. After that, you can easily apply SQL server TDE functionality, while you are still running your production system on-premise. You have to do it this way because the process of encrypting the empty database can take some time.

If you want to move SAP SQL Server databases from on-premises into Azure, then it is recommended to test that on which infrastructure you can get the encryption applied fastest by considering the following points;

  • You can't define how many threads are used to apply data encryption to the database as the number of threads mainly depends on the number of disk volumes the SQL server data and log files are distributed over i.e. the more distinct volumes, the more threads will be engaged in parallel to perform the encryption. A configuration with smaller number of volumes will lead to a small number of threads executing the encryption which results in the moderate load on the transaction log.

  • In older SQL server releases, backup compressio9n did not get efficiency anymore when you encrypted your SQL Server database. This behavior could develop into an issue when your plan was to encrypt your SQL Server database on-premises and then copy a backup into Azure to restore your data in it. Server backup compression usually achieves a compression ratio of factor 4.

  • SQL server introduced anew functionality with the SQL Server 2016 that allows compressing SQL databases also in an efficient manner.

  • If you treat the application of TDE encryption with no to little SAP workload only, then you have to test in your specific configuration if it is better to apply TDE to your SAP database on-premises or to do so in Azure which certainly offers more flexibility in terms of over-provisioning infrastructure and shrink the infrastructure after TDE got applied. 

Using Azure Key Vault

Azure generally offers a service of Key Vault to store encryption keys, while SQL Server offers a connector to leverage Azure Key Vault as store for the TDE certificates.









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