The Doppler Quarterly Spring 2019 - Page 64

Public Cloud A High- Speed Connection Public Internet User Public Cloud B Figure 4: Multicloud operations As the above figure indicates, the data migration still has to occur even if we assume we can easily migrate the application code between public clouds. The only other option is to keep the data in one public cloud and the applications in more than one. If we use that approach, we are then paying egress charges for every byte of data that moves out of the storage to the non-storage cloud. And depending on the type and amount of traffic we experience, those costs could be significant. For that matter, even duplicating the data between regions in the same cloud provider will likely incur egress costs. And in the case of replication of data, those costs are some- times doubled or tripled among multiple regions. More importantly, there is a time factor associated with moving data. If you are currently providing your application services in Cloud A, and find you have a real need to move to or replicate into Cloud B, how long will it take to move those petabytes of operational data to the new environment? And what if you still need some on-premises data (back to our AS/400 or AIX systems)? 62 | THE DOPPLER | SPRING 2019