Disaster Recovery

In the (extremely unlikely) case that all Cassandra data is lost, it is possible to recover this information by iterating through all objects stored in the object store. A rough overview of the process is as follows (for Scality sproxyd):

Index Objects Recovery

1. List index objects in object storage
2. Use HEAD requests to determine the index objects’ metadata
3. Add recovered index objects to Cassandra

Mail Objects Recovery

1. Read & refresh indices for each user/mailbox
2. Dump index data and add object information to Cassandra
3. (Optional) Look for unattached mail objects and remove them [background process]