Bugs With Backup Compression And TDE

Parikshit Savjani provides recommendations on combining backup compression with Transparent Data Encryption:

In past months, we discovered some edge scenarios related to backup compression for TDE databases causing backups or restores to fail, hence our recommendations have been

  • Avoid using striped backups with TDE and backup compression.

  • If your database has virtual log files (VLFs) larger than 4GB then do not use backup compression with TDE for your log backups. If you don’t know what a VLF is, start here.

  • Avoid using WITH INIT for now when working with TDE and backup compression. Instead, use WITH FORMAT.

  • Avoid using backup checksum with TDE and backup compression

Brent Ozar explains the risk:

When you install a new version of SQL Server, you get new features – and sometimes, you’re not told about them. For example, when 2016’s TDE compression came out, nobody told you, “If you back up across multiple files, your backups might suddenly be compressed.” You didn’t know that you had a new thing to test – after all, I don’t know a lot of DBAs who have the time to test that the new version of SQL Server successfully performs restores. They restore their production databases into the new version, test a few things, and declare victory – but testing restores FROM the new version’s backups isn’t usually on that list.

Keep up to date on those patches.

Related Posts

Aggregations And Always Encrypted

Monica Rathbun finds trouble with Always Encrypted: The real challenges started when the client began to test their application code. The first thing we hit was triggers. The table had several insert triggers associated with the columns that were now encrypted. Since the data was now encrypted the insert triggers would fail. Again, we lucked […]

Read More

Storing Credentials For Containers

Andrew Pruski shows how to store a credential using Powershell and pass it into a Docker container: I work with SQL Server in containers pretty much exclusively when testing code and one of my real bug bears is that SQL Server in containers does not support Windows authentication (unless you’re using Windocks). So when I’m working […]

Read More


September 2017
« Aug Oct »