Before migrating Azure blobs to Tigris, rehydrate anything in the Archive tier first or the drain fails with an unhelpful internal error. Remember the shadow bucket needs an S3-compatible source, and that objects you never access never migrate, so plan a verification pass that touches every key.

Context: Official Tigris migration guide (azure-blob): documents two real failure modes. First, a shadow bucket needs an S3-compatible source, so Azure Blob Storage cannot be shadowed directly and must be fronted with an S3 shim. Second, archived blobs break the migration with a generic 'an internal error occurred' message that does not name the cause. You must list and rehydrate archived blobs before retrying, and every retry walks the full container again, so do it all in one pass. Unaccessed objects also never migrate: Tigris only copies on first request.