This is clearly too much memory for too little benefit! These buffers could be recycled better.
ncw added a commit that referenced this issue
Nov 6, 2019
… size Before this change rclone would allow the user to stream (eg with rclone mount, rclone rcat or uploading google photos or docs) 5TB files. This meant that rclone allocated 4 * 525 MB buffers per transfer which is way too much memory by default. This change makes rclone use the configured chunk size for streamed uploads. This is 5MB by default which means that rclone can stream upload files up to 48GB by default staying below the 10,000 chunks limit. This can be increased with --s3-chunk-size if necessary. If rclone detects that a file is being streamed to s3 it will make a single NOTICE level log stating the limitation. This fixes the enormous memory usage. Fixes #3568 See: https://forum.rclone.org/t/how-much-memory-does-rclone-need/12743