Copy data from 1 blk device in machine A to another blk device in machine B

[DeaD_EyE]

An implementation which uses a buffer and memoryview:

import socket


host = '127.0.0.1'
port = 1337

sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
# use TCP for data transmission
sock.connect((host, port))
buffer = bytearray(1024**2) # 1MiB
view = memoryview(buffer)
with open(file, 'rb') as fd:
    while True:
        readlen = fd.readinto(buffer)
        # buffer is reused
        if not readlen:
            break
        sock.send(view[:readlen]
        # sends read data from memoryview to socket
    sock.close()

The buffer is reused for the chunks. The method readinto of a fileobject, puts the data into the buffer and returns the amount of data, which has been written to the buffer. The memoryview is just a method to have fast access on slices.
The socket object has also the function sendfile which takes a fileobject. Maybe this is the fastest implementation. I never tried it.