[CentOS] Strange performance issue on CentOS 6.7 server

On Feb 3, 2016, at 16:13, Warren Young wrote:

> A dying hard disk can do it.  HDDs try to silently paper over I/O errors, but what they can’t hide is the time it takes to do this.  If your HDD is constantly correcting errors at the oxide layer, it will be reeeeeallly sllllow.
> 
> You can try running SMART tests on it, though that’s not guaranteed to show the problem.

Well, it’s not “a” disk: it’s a HW RAID of about dozen (server grade) drives, with a VG/LV on top of that.  Are there any log files I can check that test the underlying VG/LV health status?

Alfred