@Alwin: Thanks for your help. We did our pool 4/3 size, but it still doesn't worked like we expected.
This is our test:
We have one pool with 8 osds - size 4, min_size 3.
We disable ens2f1 (cluster interface 10G) and put the command on other node:
rados bench -p SATA 60 write --no-cleanup...