Onedrive max limit on number of child items

Please describe what you are doing to trigger the bug:
Attempting to back up to Onedrive.

Please describe what you expect to happen (but doesn’t):
Backups to complete.

Please describe what actually happens (the wrong behaviour):
Backups always fail with following error log:

Running backup command from C:\Users\blahblah/.duplicacy-web/repositories/localhost/0     to back up C:/Users/blahblah
Options: [-log backup -storage beast -stats]
2020-02-11 19:15:01.546 INFO REPOSITORY_SET Repository set to C:/Users/blahblah
2020-02-11 19:15:01.546 INFO STORAGE_SET Storage set to one://duplicacy/beast
2020-02-11 19:15:10.368 INFO BACKUP_START Last backup at revision 15226 found
2020-02-11 19:15:10.368 INFO BACKUP_INDEXING Indexing C:\Users\blahblah
2020-02-11 19:15:10.368 INFO SNAPSHOT_FILTER Parsing filter file \\?\C:\Users\blahblah\.duplicacy-web\repositories\localhost\0\.duplicacy\filters
2020-02-11 19:15:10.369 INFO SNAPSHOT_FILTER Ignoring duplicate pattern: e:(?i)^PerfLogs/ ...
2020-02-11 19:15:10.370 INFO SNAPSHOT_FILTER Ignoring duplicate pattern: e:(?i)\.cache$ ...
2020-02-11 19:15:10.370 INFO SNAPSHOT_FILTER Loaded 197 include/exclude pattern(s)
2020-02-11 19:15:34.120 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\AppData\Local\ElevatedDiagnostics: Access is denied.
2020-02-11 19:16:26.424 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\Application Data: Access is denied.
2020-02-11 19:16:26.424 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\Cookies: Access is denied.
2020-02-11 19:16:28.434 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\Local Settings: Access is denied.
2020-02-11 19:16:33.340 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\My Documents: Access is denied.
2020-02-11 19:16:33.341 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\NetHood: Access is denied.
2020-02-11 19:16:33.347 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\PrintHood: Access is denied.
2020-02-11 19:16:34.819 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\Recent: Access is denied.
2020-02-11 19:16:34.851 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\SendTo: Access is denied.
2020-02-11 19:16:34.851 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\Start Menu: Access is denied.
2020-02-11 19:16:34.851 WARN LIST_FAILURE Failed to list subdirectory: open \\?\C:\Users\blahblah\Templates: Access is denied.
2020-02-11 19:16:36.335 ERROR UPLOAD_CHUNK Failed to upload the chunk 3130cdcb94a7de006e3623718a20a685465c1adb933af1711cb8837660ad3435: 400 Max limit on the number of child items was reached
Failed to upload the chunk 3130cdcb94a7de006e3623718a20a685465c1adb933af1711cb8837660ad3435: 400 Max limit on the number of child items was reached

You can change the chunk nesting level to 2 by creating a file named nesting in the storage (next to the config file) with the following content:

{
    "read-levels": [1, 2],
    "write-level": 2
}

New chunks will be written the level 2 subdirectories (write-level), while old chunks can still be read (1 is included in read-level).

BTW, how many files are in that directory (chunks/31)?

I put the nesting file with those contents right next to the config file in my OneDrive storage and got the same error.

Are there supposed to be directories within the chunks directory? For me, all of the chunk files are located directly within the the chunks directory. There are 150,000 files within that dir without any nesting.

Maybe I should do something like the following?

{
    "read-levels": [0, 1],
    "write-level": 1
}

Which version are you running? Early versions of Duplicacy didn’t support nesting chunk levels, and you need to upgrade to a more recent one in order for the nesting file to be recognized.

But, the read-levels and write-level should be specified in your way.

Also, you may want to prune a few revisions (with -exclusive and -exhaustive ) to remove some chunks so that new subdirectories can be created.

I upgraded to duplicacy-web 1.2 from 1.0 a couple hours before my original post here at which point I noticed my backups had been given me those errors for a few days.

Currently running the prune as you described…

Ok, an exclusive/exhaustive prune dropped the number of chunks down to ~100k and new backups are completing.

However, newly-created chunks are all still in the root…aka, no nesting is happening with the file nesting as a sibling to config and in the parent to the chunks directory.

hmmm, I forgot for the nesting to work, the config file needs to in a new format that has a boolean FixedNesting set to true. The easiest way to fix it might be to create a new copy-compatible storage with the same storage password, and then copy the new config file over.

The new storage must be copy-compatible, this is very important. Save a copy of your existing config file before overwriting it. Also, run a check job after that to make sure all existing chunks can be properly accounted for.