slow upload speeds

I noticed slow upload speeds to the PirateBox for 50 MB to 90 MB files. So, I tried sshing onto the PirateBox and scping files to the PirateBox, which produced upload speeds that gradually taper off until they are less than 0.6 Mbits/s when my laptop is seeing a constant signal strength of 60%. From only a few feet away and a signal strength of 75%, uploads start at about 13 Mbits/s and gradually taper off to about 2.4 Mbits/s over about a 2 to 3 minute period. Any idea why am I not seeing close to 20 Mbits/s continuously from a few feet away? I'm using PirateBox version 1.1.14 on a Raspberry Pi 3B with an Alfa AWUS036NH wifi adapter and a 64GB USB 3.0 Flash drive.

Hi,
yes, this totally depends on your USB/SD Card speed.
Up to around 50MB is cached directly into RAM and is written to disk asynchronous. So It feels totally fast to upload smaller files.
Everything beyond a certain size (this depends on your available RAM) is then written to the storage in a synchron manner. It feels like this in your example:

0 -> 50 MB : fast
50 -> e.g. 100 MB : super slow
100 -> xx : slow

The effect is because of the point you hit this boardline between RAM-ok and "not enough RAM" the operating system is starting to write down the already uploaded part & the new uploaded part.

Something to furhter readings:

s_adjustments" rel="nofollow">PirateBox' OS adjustments
Reddit: Writeup about RPi transfer speeds on PirateBox
Better Linux disk caching perfomance - vm.dirty_ration


best regards Matthias

So, I'll just have to live with the slow upload speeds. Thanks for the information.