Yes, COS file fragments will occupy storage space and incur fees. COS uses a multi-version concurrency control (MVCC) mechanism to ensure data consistency and reliability. When a file is deleted or updated in COS, it does not immediately delete or overwrite the original data, but retains multiple versions of the file. These file fragments, even if they are part of deleted or updated files, will still occupy storage space.
For example, if you upload a file to COS, then delete it shortly after, COS will not immediately reclaim the storage space occupied by this file. Instead, it will keep the file fragment in the system for a period of time (usually 30 days by default), during which you can still access and restore this file through the versioning feature. During this period, the file fragment will continue to occupy storage space and incur fees.
To reduce storage costs caused by file fragments, you can enable COS's lifecycle rules, which allow you to automatically transition files to cheaper storage classes or delete them after a specified period of time.
If you're looking for more efficient storage solutions, consider exploring Tencent Cloud's COS service, which offers flexible storage options and lifecycle management features to help optimize your storage costs.