[linux-lvm] Wierd lvm2 performance problems

[Sven Eschenberg <sven whgl uni-frankfurt de>]

Dear list,

I tried to create a PE+VG+LV ontop of a mdraid. For no obvious reason 
the lvm volume show extremely poor performance - The transferrates are 
as little as 30% of the rates on the md device itself.
In contrast creating a partition table ontop of the array gives nearly 
no performance impact.

Does anybody have the slightest idea, wht might be going wrong here?

Regards

-Sven

P.S.: I tried aligning the first PE in the VG with the mdraid chunk 
size, no difference whatsoever.