Duplicacy 2.1.0 on Windows 10
I noticed that it takes Duplicacy a long while to start the backup, so I looked at the verbose logs.
I am see a lot of errors like this:
16:12:16.202 URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
Note that eventually it does go through, but I may have 20 of these in a row at the start of the backup.
I have checked, and I am not near any of the caps at B2…
I just checked on my mac, and that backup is happening, at the same time to the same B2 account but to a different bucket, without any of these errors. Puzzling…
Here is a typical start to the backup. on the Windows 10 PC
Log file: C:\Users\username\.duplicacy\logs\backup-log-20180422-140000
2018-04-22 14:00:00.125 INFO STORAGE_SET Storage set to b2://bucketname
2018-04-22 14:00:00.126 DEBUG PASSWORD_ENV_VAR Reading the environment variable DUPLICACY_GUI2_B2_ID
2018-04-22 14:00:00.127 DEBUG PASSWORD_KEYCHAIN Reading b2_id from keychain/keyring
2018-04-22 14:00:00.127 DEBUG PASSWORD_ENV_VAR Reading the environment variable DUPLICACY_GUI2_B2_KEY
2018-04-22 14:00:00.128 DEBUG PASSWORD_KEYCHAIN Reading b2_key from keychain/keyring
2018-04-22 14:00:04.020 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:00:05.049 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:00:07.072 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:00:11.094 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:00:19.116 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:00:35.143 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:01:11.550 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:01:12.571 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:01:14.594 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:01:18.849 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:01:26.872 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:01:42.894 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:02:19.213 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:02:20.235 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:02:22.257 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:02:26.280 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:02:34.334 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:02:50.358 DEBUG BACKBLAZE_CALL URL request 'POST https://api.backblazeb2.com/b2api/v1/b2_authorize_account' returned status code 429
2018-04-22 14:03:23.333 DEBUG PASSWORD_ENV_VAR Reading the environment variable DUPLICACY_GUI2_PASSWORD
2018-04-22 14:03:23.336 DEBUG PASSWORD_KEYCHAIN Reading password from keychain/keyring
2018-04-22 14:03:23.543 TRACE CONFIG_ITERATIONS Using 16384 iterations for key derivation
2018-04-22 14:03:23.617 DEBUG BACKBLAZE_CALL URL request 'HEAD https://f000.backblazeb2.com/file/bucketname/nesting' returned status code 404
2018-04-22 14:03:23.617 DEBUG BACKBLAZE_LIST b2_download_file_by_name did not return headers
then to my eyes it finally proceeds normally.
This happens every backup.
How many threads are you using? Currently each thread needs to make the b2_authorize_account call and if there are too many it will trigger the rate limiting.
Err… I was using all of them. 64 
But I was seeing large files uploading at more than 800 Mbps on my fiber connection. That is cool!
I’ll turn it down to 16 for now.
Any suggestions for what the largest number of threads to use for B2?
B2 actually recommends you to use as many threads as you can. This limit on b2_authorize_account is a Duplicacy issue. There is no need for every thread to make this call. I’ll fix this in the next update.
So if you can run with 32 threads without seeing the 429 errors then it may be better than 16.
That’s great Thanks! Things are going well so I’m about to buy two more licenses.