When you upload data to B2, your data is stored on a Backblaze Vault. Each file you upload is stored redundantly across multiple drives, in multiple servers, in multiple locations in our datacenter. For more details, see our blog post on Backblaze Vaults.
As a result, Backblaze B2 is designed for 99.999999999% (eleven nines) of durability.
Backblaze has multiple datacenters. 3 are located in the western United States (California and Arizona). In 2019, we will also open up a European datacenter. Backblaze is committed to adding more data centers and regions over time.
All files are transmitted using an encrypted SSL connection. Developers are encouraged to add their own encryption to their files before transmitting them to B2, if desired. We have an example walkthrough on github.