I noticed a huge difference in SCP speeds by changing the client. For example the client WinSCP is much slower than FileZilla.
I am uncertain if there is any significant difference between SCP and SFTP protocols (I think SCP2 is SFTP). I know both are handled by the SSH server. On Thu, Jul 19, 2012 at 1:38 AM, Wojciech Puchar <woj...@wojtek.tensor.gdynia.pl> wrote: > maybe off topic but what is MAXPHYS set in compiled kernel? > > every BSD flavor i've seen sets it way too low for modern drives. > 2MB is smallest IMHO value that make sense on modern drives. > > you may experience lots of seeking when reading 4 files from same disk > > > > On Thu, 19 Jul 2012, David Diggles wrote: > >> On Thu, Jul 19, 2012 at 08:08:26AM +0200, Jan Stary wrote: >>> >>> >>> have you also tried -o 'Compression no'? >>> >> >> I have now. No real difference; >> >> SSH Options: [-o Ciphers=arcfour -o Compression=no] >> 64.68132476895114469583 MB/s >> 63.56096147431307883010 MB/s >> 61.69097005503488103824 MB/s >> 61.41473507203868873527 MB/s >> >> Data in the range of many terabytes, possibly up to petabytes are >> expected to go over the link, so the hpn-ssh patch used by HPC sites >> looks like the most viable for this - thanks, Michael. >> >> Dan, yes the 4 ssh processes were at 100% cpu, I guess with the >> encryption overhead. Both client and server are 8 core. There >> was no other load at the time of testing, so half cores are >> available to service disk and network load.
