Cassandra handles this pretty nicely. Files are immutable, so files are hard-linked to a snapshot directory. Copy out the snapshot directory, delete it, and thi

Cassandra handles this pretty nicely. Files are immutable, so files are hard-linked to a snapshot directory. Copy out the snapshot directory, delete it, and things are eventually consistent. We restore our MySQL and Cassandra data every day in our production DC from backups in the DR DC. It's the only way to ensure things are working. It's about 100TB of data, but things zip along nicely now that 100gig networks are (more) common.