[CentOS] LVM appears to be very expensive on CentOS 7

Tue Dec 20 00:12:21 UTC 2016
Gordon Messmer <gordon.messmer at gmail.com>

After running a long series of benchmarks, it looks like there is a very 
significant performance difference between systems using LVM and systems 
not using LVM under CentOS 7.  I'd appreciate it if anyone else can 
confirm these results.

There are a couple of other surprising aspects of the results, 
especially that the default storage configuration (LVM and 512k blocks) 
appears to be the worst configuration possible, when using RAID5 (and 
probably RAID6).