I am seeking some advice on hardware for a dedicated SSH box. I can't seem to find any performance statistics for anything but SCP/SFTP transfers and the HPN patches for fat pipes.
The goal is to support 500-1000 simultaneous SSH sessions, which are in TCP port forwarding mode only. The data travelling through the tunnel will be small (about 1KB over the course of one minute). The first question is whether crypto accelerator cards are actually useful with this type of scenario (on the server)? I looked at the OpenSSH code and it seems that it only uses crypto accelerator cards for specific tasks (keys on a smartcard). The only calls that I see to the OpenSSL functions that provide hardware acceleration (ENGINE_set_*) are in "scard.c" and "scard-opensc.c" files. So OpenSSH effectively doesn't use any hardware accelerators supported by OpenSSL? Is this correct? The second question is how much RAM/CPU would be necessary to support 500-1000 simultaneous connections (assuming no hardware accelerator support)? This will probably be AMD64 CPUs. Anybody have some statistics or guidance they can share?
