Rolling upgrade using database mirroring (and a bug in 2008 RTM)

While trawling through the latest 2008 Books Online this morning to answer a question, I noticed a new section that I hadn't seen before, which explains in detail how to perform a rolling upgrade with database mirroring. The link to the MSDN page is and below I've linked to the flowchart from that page.  

Books Online also has a lot of other "how-to" topics around database mirroring – here are some links:

Kevin Cox of the SQLCAT team also just blogged about a customer upgrade from 2005 to 2008 and some of the issues they faced. Btw – if you're not subscribed to their blog, you definitely should be – lots of cool stuff.

And now the bug. In 2008 RTM, if your database contains full-text then mirroring will not work when you perform a rolling upgrade. This is explained in KB 956017 (with a trace-flag workaround) and KB 957816, which points at 2008 RTM CU1 that has the fix in.

2 thoughts on “Rolling upgrade using database mirroring (and a bug in 2008 RTM)

  1. Hi Paul,

    I was wondering if I could use such kind of rolling upgrade on making schema changes for live databases. Would that be possible? What are your thoughts?


  2. Not with mirroring – because the mirror is an exact copy of the principal and can’t be updated to have tables with different structures – then the log records wouldn’t make sense when applied to the mirror after it catches up.

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