[linux-lvm] about snapshot performance

[Lee Rocky]

I found some reference that discuss about LVM1 volume with snapshot performance

https://www.redhat.com/archives/linux-lvm/2003-January/msg00173.html
https://www.redhat.com/archives/linux-lvm/2003-January/msg00239.html

and I follow the steps with my LVM2

command
"sync ; time dd if=/dev/zero of=filename bs=1024k count=2000"
the result is
dd write on LV without snapshots = 150MB/s
dd write on LV with 1 snapshots = 4.42 MB/s

I got very slow write performace.
but read has no problem.
is this result work as expected?

KERNEL 2.6.13
LVM2 = 2.01.15
Library : 1.01.05
Driver version: 4.4.0