SCP with Resume Feature

rapier rapier at
Sun Apr 4 02:14:18 AEST 2021

Parallelizing the transfer isn't a bad idea assuming the goal is to 
saturate the path. Its not super hard to do if you are doing it a per 
file basis but optimizing the queue can be hard to do right. That said, 
using fpart as a feeder to the queues would work. It's how parsyncfp works.

Anyway, the HPN-SSH works hard to saturate the pipe already by using 
optimized buffers, parallel ciphers (which need more work - currently 
trying to get AES-NI parallelized for CTR and chacha20), disabling the 
cipher (post authentication) for non-sensitive transfers, and so forth. 
I can push data at around 4Gb/s with a single stream between 
transcontinental hosts.

On 4/3/21 11:30 AM, hvjunk wrote:
>> On 01 Apr 2021, at 19:50 , rapier <rapier at> wrote:
>> The code is available at in the resume-scp branch. The patch file is ~1k lines long so I didn't think posting it here would be the right move.
> Given the date this was released, I had to double check… I’m just surprised it didn’t include a “—-parallel=<number>” to speedup the transfers over latency links… much more needed for me transferring data continuously between the northern and southern hemispheres  ;(
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