Object storage
Object storage vs file storage: buckets are not shared folders
A web interface can make object keys look like folders, but an S3 bucket is not an NFS or SMB share. The distinction becomes important as soon as software relies on rename semantics, locking, permissions or multiple processes editing the same file.
File storage provides filesystem semantics
Shared file storage exposes directories and files through protocols such as NFS or SMB. Applications can open a path, seek within a file, rename entries and coordinate access through filesystem behavior.
That makes it appropriate for software that was written to treat remote storage as a shared disk. Compatibility depends on filesystem semantics, not merely the ability to upload and download bytes.
Object storage uses a flat key namespace
An object key can contain slashes, but the service usually interprets the full key as one identifier. Listing with a prefix can create a folder-like user experience without creating real directory objects.
Applications built for S3 know this and structure their own naming conventions. Applications built for POSIX paths can behave incorrectly if a gateway tries to hide the difference.
Concurrency behaves differently
File applications may expect two processes to coordinate writes to one file. Object applications more often write a new object or new version and then update a reference to it.
If the workload frequently edits the middle of large files, object storage can require transferring much more data than a filesystem. If objects are naturally immutable, the object model can be simpler.
Permissions are policy-driven
File shares commonly use users, groups and ACLs mapped to paths. S3 services use access keys and policies scoped to actions and resources such as buckets or object prefixes.
Migration therefore includes an authorization redesign. Copying file permissions directly into object metadata does not automatically reproduce the same security model.
Pick the interface the application understands
Use file storage when the application genuinely requires a shared filesystem. Use object storage when the application or backup tool can work directly with object APIs and benefits from independent objects.
A clear boundary avoids relying on fragile filesystem-to-object translation layers for critical data.