On Wednesday 06 July 2005 08:52 pm, Matthew S. Hallacy wrote: > On Wed, 2005-07-06 at 10:59 -0500, Ted S. Letofsky wrote: > > Hi Randy > > > > The WIRE speed of a 10bT NIC is approximately 1 MB / Second > > The WIRE speed of a 100bT NIC is approximately 10 MB / Second > > The WIRE speed of a 1000bT NIC is approximately 100 MB / Second > > > > In reality, you can get all of 1MB / Second in 10bT > > You can get, (IF YOU PUSH HARD) about 6.5MB /Second in 100bT > > You can get, (IF YOU PUSH REALLY HARD) about 37 MB Second in 1000bT. > > What kind of CRACK are you smoking? 10mbit ethernet will move 1.2MB/s, > 100mbit ethernet will move 12MB/s, and 1000mbit ethernet/fiber will move > 120MB/s. There is no 'push really hard'. > > These are real numbers that I see *every day* on a real network, there > is no 'i get a better signal with this monster cable gold plated > ethernet so my network goes faster' when it comes to ethernet, it's > either there (full speed) or it isn't (framing errors and collisions > aside). > > [snip mostly correct jumbo frames info] > > > Also, as is obvious, you're likely going to get WAY better performance > > across NFS or (god help you) SAMBA, than you will over SSH, due to > > encryption taking up lots of bandwidth. > > The overhead with SSH is CPU, the actual encryption data isn't much > larger than the original unencrypted data. > > The overhead with SSH is not really CPU. Well it can be if we're talking low end CPUs of course. The real transfer performance factor in SSH based transfers (sftp/scp) is buffering inside the program itself (at least for OpenSSH anyways). See this URL for more info on openssh performance tuning http://www.psc.edu/networking/projects/hpn-ssh/ Another few things that will hit your network performance is crappy network cards, crappy switches, or crappy cables. You will want to make sure you have undamaged network cables, a decent switch (look at things like backplane capacity), and decent network cards. If you get a gigabit network card and run it on a 100meg switch, you will likely get more throughput than 100meg cards and a 100meg switch. I would recommend as others have to setup a private network just for backups. So you would throw an extra nic into each computer that will be involved in the backups and put them all on their own private IP network. Then the backups will not interfere with any other network activities or vice versa.