Brian from Backblaze here - expanding on Yev's answer a little, a customer has an email address/password that they login to Backblaze's datacenter with. The em

Brian from Backblaze here - expanding on Yev's answer a little, a customer has an email address/password that they login to Backblaze's datacenter with. The email address is bound to a Backblaze "Cluster" for life (at least so far we have never migrated a customer between clusters). The cluster contains a variety of services, it's the unit of scaling for our company. A single cluster scales easily up to at least 200 Vaults (probably much more, we'll let you know), and any one customer's data will be spread across pretty much all the Vaults in that cluster with enough time. A customer backs up once per hour, and each time they are told to backup to a vault with spare space on it with no affinity. Theoretically it might be possible all your data lands on one vault, but it's really unlikely. Vaults belong to a cluster - so your backup only puts data on the group of Vaults assigned to that one cluster, and the vaults in that cluster don't contain data from customers on OTHER clusters.