ssh error - Write failed: Broken pipe

[Gary Dale <garydale@rogers.com>]

I'm connecting at various times to different Debian/Squeeze servers from 
my Debian/Wheezy workstation using ssh. No matter which server I connect 
to, I find that if I move a lot of data on the remote server, I get 
kicked out of my ssh session with a "Write failed: Broken pipe" error.

This doesn't happen immediately. It usually occurs after some period of 
time, during which time the cp or rsync command is moving data from one 
location to another (gigabytes typically). So far as I can tell, the 
operation finished successfully.

This is repeatable 100% of the time.

typical commands:
cp /tmp/backups/* /media/dvd
rsync /tmp/backups/file /media/dvd/file

(I'd be doing this to "fix" a faulty file copy onto Blu-Ray media, for 
example)

I have even encountered it with
if cmp /media/backupmedia/backup-set /home/shares/backup/backup-set; 
then echo "OK"; fi

although this sometimes works. I think it depends on the exact size of 
the file. The cmp operation seems to not trigger it as fast as rsync or cp.

If I'm not moving large amounts of data on the server, the ssh session 
is stable and will sit for as long as I want. I only get disconnected 
when I'm moving data around on the remote machine.

Any ideas?