[root@dev ~]# iftop -h
iftop: display bandwidth usage on an interface by host

Synopsis: iftop -h | [-npbBP] [-i interface] [-f filter code] [-N net/mask]

   -h                  display this message
   -n                  don't do hostname lookups
   -N                  don't convert port numbers to services
   -p                  run in promiscuous mode (show traffic between other
                       hosts on the same network segment)
   -b                  don't display a bar graph of traffic
   -B                  Display bandwidth in bytes
   -i interface        listen on named interface
   -f filter code      use filter code to select packets to count
                       (default: none, but only IP packets are counted)
   -F net/mask         show traffic flows in/out of network
   -P                  show ports as well as hosts
   -m limit            sets the upper limit for the bandwidth scale
   -c config file      specifies an alternative configuration file

iftop, version 0.17
copyright (c) 2002 Paul Warren  and contributors

I cannot seem to find it in the manual. Well, no reference to compression that I could find!

I’m not sure what monitoring tools you have available, or what your network people are reporting on. I’ve found iftop very useful because you can run it directly on the server. I just noticed that there is an option available to monitory per-port as well. With that, you could confirm the actual bandwidth that the mysql traffic is consuming.

As for SSH compression, I just a enabled in in ~/.ssh/config like this:

Host remote.domain.com
    Compression yes
    CompressionLevel 9

Would you mind that I ask you a simple question? I have enabled replication compression in my application both in master and slave as slave_compressed_protocol | ON
But I ask my network people and it seems we haven’t got the noticable bandwidth gain? So Could you give us a clue? By the way, how could we compressed by SSH?
Many thanks,

Don