Single cluster node restore
Hi. I have a question about Cassandra backup-restore strategies. As far as I understand Cassandra has been designed to survive hardware failures by relying on data replication. It seems like people still want backup/restore for case when somebody accidentally deletes data or the data gets otherwise corrupted. In that case restoring all keyspace/table snapshots on all nodes should bring it back. I am asking because I often read directions on restoring a single node in a cluster. I am just wondering under what circumstances could this be done safely. Please correct me if i am wrong but restoring just a single node does not really roll back the data as the newer (corrupt) data will be served by other replicas and eventually propagated to the restored node. Right? In fact by doing so one may end up reintroducing deleted data back... Also since Cassandra distributes the data throughout the cluster it is not clear on which mode any particular (corrupt) data resides and hence which to restore. I guess this is a long way of asking whether there is an advantage of trying to restore just a single node in a Cassandra cluster as opposed to say replacing the dead node and letting Cassandra handle the replication. Thanks.
Rename User
Hello. I know that Cassandra does not natively provide functionality for renaming users, just for altering passwords. I implemented it in my application by creating a user with the new name and original password, granting it the privileges of the original user and dropping the original user. The above procedure seems to work as expected, but I have been wondering if the reason why Cassandra does not support renaming natively is because it is actively trying to prevent anybody from doing this. Are there any potential (security?) issues with user renaming and/or the outlined procedure? Thanks. P.
