frantisek holop wrote: > hi there, > > poking around in the HP ssh docs, one can see the following in the FAQ: > > Q: How is the performance of HP-UX Secure Shell? > A: Compared with conventional file transfer methods, the scp command > is 2 - 3 times slower than rcp, and sftp is 2 to 3 times slower than > ftp. This is because HP-UX Secure Shell authenticates both the server > and users, and encrypts both the data and the password. In addition, > HP recommends you use the /dev/random device on your system to > significantly speed up program initialization. > > i find it interesting that most of the user community perceives > scp/sftp multiple times slower then their not encrypted counterparts.
I find that interesting, too. I was just explaining to my GF's six-year-old niece yesterday that you shouldn't believe everything someone says. Been doing some interesting tests recently... scp'ing large (100M+ files) from a Celron 566 to a PIII-750 went at about 4MB/s, using fxp cards on both sides. Somewhat less than half wire speed. Room for improvement, certainly, but not three times. And that's on two-generation old hardware! (and several switches, a router, and a firewall between them) scp'ing the same large files from the same PIII-750 to an AMD64 3000 processor on the same subnet (though with a LOT of switches between them) managed over 8MBs (sk(4) chip on the amd64, 100Mbps network). Not going to get much better than that. (Well..actually, I *did* get impatient, as there was several hundred gig to transfer, so I pulled the disk out of the PIII and put it in the amd64 and did a disk-to-disk copy). > i think it would be very nice to have a performance page on the openssh > site describing what should be expected, what is "normal" and the > intended performance of ssh to clear up possible misunderstandings. > (like mine here) too many variables. I'd like to grab another amd64 system and a gigabit switch and try my test again, but on modern HW, you should be moving a fair chunk of data. There are some things you should just test yourself, and find your own bottlenecks. BTW: that PIII-750 had a very slow disk system for its age -- UDMA2. The cables were way too long to run at a more respectable rate. Note the difference in the network. And so on and so on. Oh, and OpenSSH is very multi-platform...again, more variables. The people complaining that they didn't get the "expected" performance they saw on such a page would be a never ending nightmare. For example, when I first started writing this, I forgot that the my two test cases involved one common machine, but two very different network paths... Nick.
