# Slow Upload to B2
**URL:** https://forum.duplicati.com/t/slow-upload-to-b2/10388
**Category:** Support
**Created:** [July 30, 2020, 2:13am UTC](https://forum.duplicati.com/t/slow-upload-to-b2/10388 "2020-07-30T02:13:39Z")
**Posts on this page:** 4
**Page:** 1
### Author:  [@p.public](https://forum.duplicati.com/u/p.public)
#### Post date: [July 30, 2020, 2:13am UTC](https://forum.duplicati.com/t/slow-upload-to-b2/10388/1 "2020-07-30T02:13:39Z")
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?
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### Author:  [@HolyPanda](https://forum.duplicati.com/u/HolyPanda)
#### Post date: [August 1, 2020, 10:00pm UTC](https://forum.duplicati.com/t/slow-upload-to-b2/10388/2 "2020-08-01T22:00:22Z")
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](https://forum.duplicati.com/t/backblaze-b2-slow-upload/4128/30)
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### Author:  [@jobec](https://forum.duplicati.com/u/jobec)
#### Post date: [August 17, 2020, 1:42pm UTC](https://forum.duplicati.com/t/slow-upload-to-b2/10388/3 "2020-08-17T13:42:10Z")
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.
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### Author:  [@ts678](https://forum.duplicati.com/u/ts678)
#### Post date: [August 21, 2020, 1:44am UTC](https://forum.duplicati.com/t/slow-upload-to-b2/10388/4 "2020-08-21T01:44:26Z")
Welcome to the forum @jobec
> [@jobec](#):
>
> Like something actively throttles the upload.
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](https://duplicati.readthedocs.io/en/latest/07-other-command-line-utilities/#duplicaticommandlinebackendtoolexe) can do upload to a URL similar to the one you can get from [Export As Command-line](https://duplicati.readthedocs.io/en/latest/03-using-the-graphical-user-interface/#exporting-a-backup-job-configuration) (don’t upload into your actual backup).
> [@jobec](#):
>
> the speedtest to backblaze is way faster.
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.