How to find out the reason for the low speed of lvm?

Question

Debian

Deployed Debian 9.
Created several logical lvm partitions.
1 - lvm on raid1 (2hdd)
2 - lvm 1 hdd
3 - lvm 3 hdd
On 2 and 3 zoo hdd by 2tb
All 3 partitions are identically formatted in ext4.
Smart indicators without errors.
Copying from a gigabit network to lvm3 occurs at best at a speed of 5 mbit / sec.
When copying to other lvm, the speed is 50-60 under the same conditions.
Previously, all disks were a single lvm and this was not observed.
What can be wrong? How to fix?

Answer 1

did short , long testing?
Most likely the reason is that there is a leapfrog with added partitions in the LVM volume.