AWS Glacier offers Vault Lock, which enables compliance policies like “write once read many” (WORM). Google Cloud Platform Storage does not. Does OpenStack Swift or Ceph offer any similar compliance features out of the box?
Openstack Swift appears to not have immutability yet. Neither does CEPH. There are object options for WORM, but most places just use one of the more traditional NAS options. Most enterprise storage vendors have a WORM offering that's got a track record of compliance.