Subject: very big file copy from 1 machine to N machines
To: None <>
From: Emmanuel Dreyfus <>
List: netbsd-users
Date: 08/03/2002 13:06:16

I need to copy several gigabytes from a device file (it's a disk
partition) to a pool of machines on the same ethernet network. 

For now I'm doing this using netcat, making as many TCP streams as
targets I have. This does not scales very well.

My goal would be to use some reliable broadcast or multicast file
transfer protocol. I tried MDP (IMM successor) and AFDP with no luck: 

Due to some bugs, MDP is unable to use efficiently the available
bandwidth and turns to be too slow. 

AFDP takes advantage of the bandwidth, but was unable to handle reading
from a device file. I patched this, but it still seems to have trouble
handling very big files: when transfering several hundred of megabytes,
some clients miss too much packets and request for data resend which is
out of the server's cache, the server won't resend, and the transfer

Anyone has some experience or some idea about how to acheive this?

Emmanuel Dreyfus