There are actually no limit for blob size. The clients decide the blob size. It is limited by available memory and concurrency. By default, the filer client us

There are actually no limit for blob size. The clients decide the blob size. It is limited by available memory and concurrency. By default, the filer client uses 8MB. Each identifier is as <volume_id, file_key, cookie>. With volume_id, you can locate the volume server. So the volumes are portable and can be moved around.