I’ve recently had some trouble with SQL Server Integration Services behaving badly. SSIS manages its own memory use, and ordinarily does a good job. By throttling inputs SSIS can run vast amounts of data through a data flow without using much memory or swapping to disk. Sometimes this goes horribly wrong, though, and you find your SQL Server database is hard faulting out of physical RAM because SSIS has gone and claimed 110% of the total RAM, much of which was already occupied.
Read the rest on the Optimal BI blog.