Copy-on-Write Technology
The copy-on-write technology that Microsoft first introduced with SQL Server 2005 is at the core of both database mirroring and database snapshot capabilities. How it is used in database mirroring is explained in Chapter 20. In this section, we walk through a typical transactional user’s update of data in a source database.
As you can see in Figure 32.5, an update transaction is initiated against the AdventureWorks database (labeled A). As the data is being updated in the source database’s data page and the change is written to the transaction log (labeled B), the copy-on-write technology also copies the original source database data page in its unchanged state to the sparse data file (also labeled B) and updates the ...
Get Microsoft® SQL Server 2008 R2 Unleashed now with the O’Reilly learning platform.
O’Reilly members experience books, live events, courses curated by job role, and more from O’Reilly and nearly 200 top publishers.
