Slow Upload to B2

I am trying to upload a backup to b2 and it is incredibly slow. My initial upload was fairly quick and was able to upload about 15 GB in short order. Now, I am trying to do another upload a week later and it is much slower. It seems to be hung on “##### files need to be examined (##GB)”. My upload speed on my computer is shown as 2kB/s. If I try and upload to b2 with a direct call to their s3 buckets using amazon aws-cli, it is much faster (~1MB/s). My command for backing up to b2 is fairly simple. It is just:

duplicati-cli backup “b2://bucket” “/home” --auth-username=xxx --auth-password=xxx --compression-module=zip --no-encryption=false --passphrase=xxx and then several excludes.

Is there something I am doing wrong here?

What version are you on? Updating to 2.0.5.1_beta fixed my slow B2 upload issue.
https://forum.duplicati.com/t/backblaze-b2-slow-upload/4128/30

I’m running that exact same version, but I never get speeds above 1.13MB/s while the speedtest to backblaze is way faster.

Looking at the profiling log, it looks like each concurrent upload never goes above 300KB/s or so. Like something actively throttles the upload.

Welcome to the forum @jobec

Have you ruled out a manual throttle setting using the “Throttle Settings” at top of GUI or throttle Options?

Does one separate upload run faster if you reduce asynchronous-concurrent-upload-limit from default 4?

If you want a more plain-vanilla upload test, Duplicati.CommandLine.BackendTool.exe can do upload to a URL similar to the one you can get from Export As Command-line (don’t upload into your actual backup).

and also reports in Mbit/s, so be sure you divide by 8 if you’re comparing to MByte/s like Duplicati’s values.

I’m not using B2 lately, but when I did, filling my cable modem’s 6 Mbit/s uplink (750 KByte/s) was typical…

Although I think it needs a new bucket, Backblaze S3 speed might differ due to internal design at their end.