April 11, 2010 at 9:00 am
An extract from the Microsoft Technical Article Database Encryption in SQL Server 2008 Enterprise Edition
"The performance impact of TDE is minor. Because the encryption occurs at the database level, the database can leverage indexes and keys for query optimization. This allows for full range and equality scans. In tests using sample data and TPC-C runs, the overall performance impact was estimated to be around 3-5% and can be much lower if most of the data accessed is stored in memory. Encryption is CPU intensive and is performed at I/O. Therefore, servers with low I/O and a low CPU load will have the least performance impact. Applications with high CPU usage will suffer the most performance loss, estimated to be around 28%. The primary cost is in CPU usage, so even applications or servers with high I/O should not be too adversely affected if CPU usage is low enough. Also, because the initial encryption scan spawns a new thread, performance is most sharply impacted at this time; expect to see queries perform several orders of magnitude worse. For disk space concerns, TDE does not pad database files on disk although it does pad transaction logs as previously noted in How Data is Encrypted."
Also see:
Paul White
SQLPerformance.com
SQLkiwi blog
@SQL_Kiwi
April 11, 2010 at 9:56 am
You're welcome
Paul White
SQLPerformance.com
SQLkiwi blog
@SQL_Kiwi
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