Glossary

Data mobility

Data mobility is the ability to move data between storage systems, applications, sites and clouds while it stays accessible, intact and usable. Copying the bytes is the straightforward part; the harder part is carrying the metadata and rules that give those bytes their meaning.

Five ways data moves

  • Bulk copy: a one-time transfer of a dataset with a copy or sync tool.
  • Replication: continuous copying to a second system, described under data replication.
  • Lifecycle rules: policy-driven movement of aging data to cheaper tiers, as in storage lifecycle management.
  • Gateways: local access while data lands elsewhere, through a cloud storage gateway.
  • Migration projects: planned moves between platforms, covered under cloud migration.

Migration is one event. Mobility is the standing capability to move data repeatedly and in several directions. An estate that relies on one method, usually bulk copy, tends to rebuild its tooling for every project, while one that uses standard interfaces across systems can reuse the same paths for tiering, recovery and exit.

Content arrives; rules go missing

Object tags, user-defined attributes, access permissions, version history and retention or legal-hold dates are stored separately from the content, and many tools copy only the content. Permissions may point to identities that do not exist on the target. Versions may collapse into a single latest copy. Retention locks may be replaced with defaults, so records become deletable early. A tool that drops these without raising an error is the hardest case, because every checksum matches and the move looks successful until an audit.

Verifying a move before retiring the source

  1. Compare object counts and total size between source and target.
  2. Check content checksums on a sample of objects.
  3. Compare tags, permissions, version counts and retention dates on a sample drawn across the whole dataset, not only the newest objects.
  4. Retire the source only after all three checks pass.

Open interfaces help: the S3 API defines metadata and retention fields that compatible systems are expected to preserve, but the copy tool still has to read and write them. Mobility is the capability that counters data gravity, and its limits are mostly bandwidth and egress fees.