Directory Buckets / Hot Object Storage
A purpose-built storage tier designed for single-digit millisecond latency, using a directory-based namespace within a single Availability Zone. Trades multi-AZ durability for consistently low access times.
Summary
A purpose-built storage tier designed for single-digit millisecond latency, using a directory-based namespace within a single Availability Zone. Trades multi-AZ durability for consistently low access times.
Directory Buckets represent the high-performance end of S3 storage. They fill the gap between standard S3 (high durability, variable latency) and local disk (low latency, no durability), enabling latency-sensitive workloads like ML training and real-time analytics to use object storage.
- Directory Buckets are single-AZ only. Data is not replicated across AZs, so they are not suitable as a sole durable store for critical data.
- The directory-based namespace is not the same as a filesystem. It enables faster listing within directory structures but does not provide POSIX semantics.
scoped_toS3, Object Storage — a specialized storage tier within the S3 ecosystem- S3 Express One Zone
implementsDirectory Buckets / Hot Object Storage — the AWS implementation solvesCold Scan Latency — single-digit ms access eliminates cold-start overheadconstrained_byVendor Lock-In — currently an AWS-specific feature
Definition
Purpose-built storage tier for single-digit millisecond latency, using directory-based namespace within a single Availability Zone. Trades multi-AZ durability for dramatically reduced latency.
Standard S3 has ~50-100ms per-request latency. AI/ML inference, real-time analytics, and interactive workloads need lower latency. Directory buckets co-locate data with compute for speed.
Connections 4
Outbound 2
scoped_to2Inbound 2
Resources 3
AWS docs for S3 Express One Zone directory buckets, the high-performance single-digit-millisecond storage class for latency-sensitive workloads.
Product page for Express One Zone covering pricing, feature overview, and use-case guidance.
AWS Storage Blog introducing Express One Zone with architecture details and performance benchmarks.