How to track down abysmal performance ata - raid1 - crypto - vg/lv - xfs

[Christoph Hellwig]

On Wed, Aug 04, 2010 at 09:35:46AM +0200, Dominik Brodowski wrote:
> How can I best track down the cause of the performance problem, 
> a) without rebooting too often, and
> b) without breaking up the setup specified above (production system)?

So did you just upgrade the system from an earlier kernel that did not
show these problems?  Or did no one notice them before?