For many customers, remote backup and archiving will be their first steps on a journey to cloud. For others, it is an integral part of a complete cloud-based technology delivery model. Technically, it doesn’t matter whether it is a standalone managed backup service or part of broader solution, the philosophy is the same.
Below is a concept diagram showing the flow of data as part of a backup and archiving service:
At the top, we have the primary data source, i.e. the actual data to be backed up. This could be taken from the live storage of a cloud deployment, from on-premise PCs and servers, from a SAN in a colo rack, or from any other source of data.
Once the data has arrived at the service provider, it needs to be processed. Typically, this will involve a three-step process. Firstly, de-duping to ensure that the same data is not stored multiple times (especially important as part of a regular automated backup). Secondly, the data is encrypted for security (so that not even the service provider can access the core data). Finally, it is compressed to reduce the storage payload (to minimise the customer’s cost).
Next, the data is stored in the SAN (typically an array of spinning disks or solid state drives) in one zone of the service provider’s datacentre. The frequency of the backup is scheduled (e.g. twice a day, noon and midnight) with the process being automated from that point onwards. Snapshots are available dating back as far as the storage remains in the backup environment. The customer can restore the data image based on these backups at a company, machine or document level. After a pre-programmed number of days, the data moves into the long-term archive, at which point the snapshot is frozen and the data will no longer be over-written.
Finally, many service providers also backup their own storage environment to a second zone, in a geographically diverse datacentre, for redundancy. In the event of a zone 1 site outage or a hardware failure, the provider would be able to restore either services or data from zone 2.