About Azure Blob Storage
Object storage at exabyte scale, built and run by Microsoft Azure.
Azure Blob Storage is the object storage service that Microsoft made generally available in 2010 as part of Azure Storage. It holds objects inside containers, addressed by a name, and the design target is straightforward: store any amount of unstructured data, reach it from anywhere, pay for what you use. Microsoft publishes a durability target of eleven nines (99.999999999%) on geo-zone-redundant configurations and a default availability target of 99.9% on the Hot tier, with read access geo-redundant variants reaching 99.99%.
Around the core PUT and GET surface sit a stack of features that matter for analytics: three blob types (block blobs for general object storage, append blobs for log workloads, page blobs for VM disks); access tiers from Hot through Cool and the newer Cold tier added in 2023, down to Archive for rarely read history; redundancy options from LRS and ZRS inside one region to GRS, RA-GRS, GZRS and RA-GZRS that replicate across regions; lifecycle management rules that move blobs between tiers automatically; soft delete, versioning and immutable storage for recovery and WORM compliance; private endpoints, RBAC, customer-managed keys and Azure AD authentication for governance. Azure Data Lake Storage Gen2, the variant with hierarchical namespace turned on, layers a real directory tree and POSIX-style ACLs on top of the same storage account, which is what Synapse, Fabric, Databricks and Snowflake external tables read against when teams use Azure as their lakehouse foundation.