By default Backblaze does not have any file size restrictions:
Backblaze prioritizes smaller files, and uploads larger files later. This might explain why it seems that Backblaze was uploading multiple files faster before, and now uploads less files slower. To avoid needlessly hogging your bandwidth Backblaze will only upload files larger than 30MB once every 48 hours.
Once a file has been uploaded, modifications to the file will be handled differently depending on the file size and structure.
- If a file is under 30MB, the whole file will be reuploaded when it is changed.
- If it is over 30MB, the file is broken into 10MB chunks to be uploaded.
- If the file simply has data added to the end of the file, only the last chunk will be reuploaded. If data is entered into the middle of the file, every chunk after that point will need to be reuploaded, because the data has been pushed back and each following block changed.
If you have extremely large files that are slowing down your backup, you may want to consider excluding the large files from backup.