CineGrid

Team members: Jurgen Schulze, Shaofeng (Leo) Liu

Copying large files over multi-gigabit networks

• Download latest version of UDT file transfer tool. The version we have been using is http://ivl.calit2.net/wiki/files/revisedudt3.3.tar.gz. Untar and unzip the file to a directory of your choice.

• Optimize network settings:
  • Change maximum UDP buffer size (read and write) on sender and receiver: edit /proc/sys/net/core/rmem_max and /proc/sys/net/core/wmem_max. The number in the files determines the buffer size in bytes. We suggest the size to be 16MB (=16777216 bytes) for each of the buffers, which is the maximum allowed size.
  • Set buffer sizes in application, before the sockets connect:

   int feng_temp=256000;
   UDT::setsockopt(serv,0,UDP_SNDBUF,&feng_temp, sizeof(int));

   int feng_mss=8800;
   UDT::setsockopt(serv,0,UDT_MSS ,&feng_mss, sizeof(int));

   int feng_recvbuf=40960000;
   UDT::setsockopt(serv,0,UDP_RCVBUF,&feng_recvbuf,sizeof(int));

• The following commands are called from the directory udt3.3/app/

• Run the sender:

 ./sendfile

• Run the receiver:

 Syntax: 
 ./recvfile <IP address/hostname of sender> <port number> <remote source file name> <local destination file name>
 Example: 
 ./recvfile 127.0.0.1 9000 /home/jschulze/data/largefile.tif ./temp.tif