@olivierlambert about local mount vs xo nfs. i made new tests, XO implementation works not worse than native. That really good result.
local nfs
Size: 5.98 GiB
Speed: 70.76 MiB/s - 81.33 MiB/s
xo nfs
Size: 5.98 GiB
Speed: 79.01 MiB/s - 82.22 MiB/s