Restoring the Backup

"Nobody needs backups; everyone needs restores" is a platitude – both obvious and inevitable: The best of all backups is worthless if it cannot be restored properly. Luckily, the Trove developers have considered the restore issue and offer the option of restoring a database directly via the Trove API (Figure 5). This works differently, however, than users may be accustomed to from classical setups.

Figure 5: With Trove, restoring a database from backup is as easy as creating it.

In the first step, the user starts a completely new database and tells Trove to restore the backup. In the second step, the server automatically assigns the (public) IP address used previously by the old database to the new database. In the last step, the admin deletes the old database so that it completely disappears from Trove. Clients then reconnect to a database with valid data, without the user having to change anything in terms of the configuration of their components.

The command for starting a database from an existing backup would look like this:

trove create guest-2 10 --size 5 --backup <ID>

You can use trove delete <ID> to delete the old database after completing the migration.

Although backups in Trove are neatly implemented, things do not look as friendly in the case of snapshots: Support for snapshots is currently completely absent in Trove, but admins can at least resort to the snapshot feature in Nova, which creates a snapshot of the entire VM, not just the database.

Conclusions

Although the individual Trove components can be integrated relatively easily into an existing OpenStack platform, admins still need to be prepared for a huge amount of work: As a platform operator, even creating the required images for Trove is not as easy as one would like. Storage is of particular importance: Operators would do well to define their own needs very precisely. However, from the user's point of view, Trove is fun, if the platform operator does their work well. Trove significantly facilitates the task of managing your VMs for databases.

The Author

Martin Gerhard Loschwitz is Head of Cloud with iNNOVO Cloud, where he focuses on high availability, distributed storage, and OpenStack.