Limits

Overview of the technical limitations of centron and cBacks: encryption, volume restrictions, performance implications and recommendations for I/O-intensive systems.

Encryption and accessibility:

cBacks files may not be encrypted at the time of storage, but they are not accessible externally.

Inclusion of volumes:

Automated cBacks operations, similar to those on DigitalOcean, cannot include volumes. For volumes, you could carry out manual cBacks operations using volume snapshots.

Optimisation for systems with low write activity:

cBacks may be optimised for systems with low write activity. For systems with active database write operations and other high-frequency I/O workloads, an application-specific backup may be more suitable.

Snapshot mechanism:

The snapshots used to create the point-in-time dataset could utilise a copy-on-write mechanism. This enables virtually instantaneous snapshots, which is beneficial for data consistency and incurs minimal overhead for the actual creation of the cBacks.

Performance losses with copy-on-write:

Until the backup process is complete, copy-on-write implementations may experience a drop in performance when new write operations occur after the snapshot has been created. This could particularly impact performance in busy, I/O-intensive workloads. This impact on performance disappears if the snapshot is automatically deleted after the backup operation.

Impact on databases:

Databases could be particularly affected, as most database operations are heavily dependent on disk I/O. This could slow down both the application and the backup process, or in some cases even cause them to fail. Operations that remain in memory or in the cache and have not been written to the hard disk could be lost. Crash-consistent cBacks systems always save what is on the hard disk, but never what is in memory or the cache.

Application-specific backup methods:

If you are running a database or another application that generates a high I/O load, choosing an application-specific backup method might be a better option. Many databases have backup solutions specifically tailored to these systems.

These adjustments are tailored to centron’s ccloud³ VMs and are based on the characteristics and practices of centron and cBacks. It is important to check the specific guidelines and features of centron, as these may differ from those of DigitalOcean.