Corruption occurs on the page of secondary replica when you change the secondary replica to unreadable

Corruption issue should be treated as critical, as if gone undetected they are difficult to recover from without data loss.

The corruption can happen when changing readability property of the secondary database.  However only if the database is using data compression.  Please review and test the linked CUs if you are using AlwaysOn Availability Groups and Data Compression with your environment.

Microsoft SQL Server 2012 SP2 CU6 (link) and Microsoft SQL Server 2012 SP1 CU16 (link) released.


  1. Mohit,

    Do you have an idea at what level was this issue discovered? Is it an SP2 only issue or maybe introduced in a CU post SP2?



  2. Hey Chris,

    I do not know when it was introduced top of my head. I will look into it and circle back either later today or by end-of-day tomorrow.


  3. To complete circle here, for other readers. Chris confirmed this with Bob Ward (Principal Architect Escalation Engineer, Microsoft CSS) this issue has been present since SQL 2012 RTM. Guess the combination of Compression + AlwaysOn Secondaries that are readable has not been tried to date.

    — Thanks Chris/Bob 🙂

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