Trying to pick up Duplicati after jumping ship from Crashplan home before it goes under. Have some questions.

It looks like Duplicati is going to be the best option for me. Everything seems pretty straight forward and easy for the most part, which is what I want in backups. However, nothing new can go without some questions. I've gone to the community forums in the Duplicati docker thread and some people have chimed in, but I still don't feel like I've gotten the answers that I need.

First off: Remote volume size

Duplicati's default is set to 50MB and from what I understand, this is to make it easier to push them to the cloud. Since I won't be using cloud (I have a 400GB cap), I'll be pushing backups to a local USB drive. After trying a backup previously using the default 50MB, the backup seems to go incredibly slow due to the long pauses in between the creation of each volume. After a lot of research, I still haven't been able to find any clear answer on what sizes should be used in different scenarios.

I set the volume size to 1GB. I don't know if this is ideal or not since there's really no place that explains it, but I do notice a little improvement in the speed. However, it's still incredibly slow, which brings me to my next question.

What speeds should I be seeing?

With a 1GB volume size, no encryption, and no compression, it took about three hours to back up 30GB worth of test files. That seems really slow to me. Having compression on or off doesn't seem to make a difference in speed.

I am now attempting a real backup of my 1.7TB worth of data with 1GB volume sizes, no encryption, and default compression. It's been running for about 16 hours and in that time it's processed about 330GB. I've been monitoring the /tmp folder and my backup target. The slowness is in the creation of the volumes. They are being generated at about 5 MB/s. Once the volumes are created, the actual process of moving them to the USB drive is what you would expect, going at about 100 MB/s. It takes 2-3 minutes to create the the 1GB volume. It then sits there for 30-60 seconds before sending the volume to the drive and starting on the next. I'm sure it actually is doing something when I say it just "sits there", but I still included that since it does add to the time.

Since this is my first experience with Duplicati, I don't know if this slowness is what's expected, or if I'm doing something wrong. Is there a way I can speed this up? I would consider this current running backup still before the point of no return and would be willing to cancel it to make any recommended changes.