HEP Tape Archive definition

Proposal

The proposal should address all issues regarding the use of tape as ‘true archive’

• Define the tape experts definition of ‘archive’
• To support the DAM discussion started at the Jamboree
• To prevent the use of tape as random access device in the future

What makes archives true (German you had more items for this list. Can you add them please?)

• • German's list:
  • Data needs to be organised in Containers (example: tar files) which are opaque (the container is the storage unit, rather than the individual files).
  • Containers need to have a minimum size, in terms of volume, files, or even age.
  • Containers should become read-only once they are migrated to tape. This is to avoid fragmentation and versioning within container payloads.
  • All required metadata for the payload should be within the container itself. The metadata does not need to be seen from outside the container.
  • End-user access to containers should be controlled or even better, restricted (ideally: banned). Alpha users from experiments are responsible for container get/put operations.
  • A container should have a maximum lifetime defined (infinite is possible, but needs to be set explicitly).

• Data 10 years life time? more?
• Near-line or shelf?
• Do we need duplicates
• Lifetime on data needed?
• Simple IO: put, get , delete (do we want or need ‘ls’?)
• Metadata handling
• Type of protocol to access the archive
• Restrict access to the archive to prevent misuse and propose how to limit this access

-- VladimirBahyl - 07-Jul-2010