For block level backup, a full image level backup is created of a file system from production storage at a production server to random access storage at a backup server. A mounted image is created from the full image that exposes a block level representation of the file system of the production server for read operations in a file level format. File enumeration is performed on the mounted image for files. Block level read operations are monitored while the files are being enumerated. During monitoring, blocks that are read for the read operations are marked as meta-data blocks. Blocks that are not marked as meta-data blocks are identified as data blocks. The data blocks are migrated to sequential storage, while leaving the meta-data blocks on the random access storage, wherein the data blocks form a backup image.