sftp/scp performance testing

[maf at appgate.com]

On  8 Jan, Tobias Ringstrom wrote:
\>>     My method for testing OpenSSH performance has been something
>> along the lines of:
>> 
>>     cat /dev/zero | ssh user at host "cat > /dev/null"
>> 
>>     and then monitoring network traffic using another tool. 
>>     Something like:
>> 
>>     cat /dev/zero | cpipe | ssh user at host "cat > /dev/null"
>> 
>>     would also work.  This method is useful because the zeronum
>> generator is faster than any randomizer, and it completely filters
>> out disk I/O.

I once did something similar to test the performance of an ssh-based vpn
(but I used ttcp). And got quite surprised when I got a throughput over
100Mbit/s when the vpn-nodes were connected with a 10Mbit/s network. The
answer however was simple, they had compression enabled:-) From that
point on I always use random-data to do performance testing.

	/MaF