During a chunked upload, the file is split into small parts and these parts are uploaded. If some parts failed to upload, the whole file does not have to be re-uploaded, only the parts that failed. All this is done in the background in UploadWizard.
It provides better reliability not just for UploadWizard, but also for bots using the API, especially for files uploaded through the API.
|Chunked upload fails (2012)
||Stashed upload manual draft
|Chunked upload tracking bug
||Uploadstash errors tracking
- MediaWiki documentation about chunked upload
- Help:Server-side upload
- Uploading a new version with chunked uploads
- Special:UploadStash, which sometimes allows completing a chunked upload when the UploadWizard fails.