# RGW Bucket Resharding Without Pausing

DevFeed: [RGW Bucket Resharding Without Pausing](<https://devfeed.tech/articles/rgw-bucket-resharding-without-pausing-12337.md>)

Original publisher: [Read original article](<https://ceph.io/en/news/blog/2026/rgw-improved-resharding/>)

Author: Daniel Alexander Parkes, Anthony D'Atri

Published: 2026-02-01T00:00:00Z

Content type: article

Language: en

Sources: [Ceph Blog](<https://devfeed.tech/sources/ceph-blog.md>)

Topics: [systems](<https://devfeed.tech/topics/systems.md>), [Scalability](<https://devfeed.tech/topics/scalability.md>), [Architecture & Design](<https://devfeed.tech/topics/architecture-design.md>), [cloud-infrastructure](<https://devfeed.tech/topics/cloud-infrastructure.md>)

Tags: [2026](<https://devfeed.tech/tags/2026.md>), [article](<https://devfeed.tech/tags/article.md>), [blog-post](<https://devfeed.tech/tags/blog-post.md>), [ceph](<https://devfeed.tech/tags/ceph.md>), [concurrent](<https://devfeed.tech/tags/concurrent.md>), [deep-dive](<https://devfeed.tech/tags/deep-dive.md>), [en-article](<https://devfeed.tech/tags/en-article.md>), [en-blog-post](<https://devfeed.tech/tags/en-blog-post.md>), [io](<https://devfeed.tech/tags/io.md>), [operational](<https://devfeed.tech/tags/operational.md>), [operations](<https://devfeed.tech/tags/operations.md>), [performance](<https://devfeed.tech/tags/performance.md>), [production](<https://devfeed.tech/tags/production.md>), [rgw](<https://devfeed.tech/tags/rgw.md>), [s3](<https://devfeed.tech/tags/s3.md>), [scalability](<https://devfeed.tech/tags/scalability.md>), [scale](<https://devfeed.tech/tags/scale.md>), [storage](<https://devfeed.tech/tags/storage.md>), [systems](<https://devfeed.tech/tags/systems.md>)

## AI overview

The article explains how Ceph Tentacle introduces near-zero-impact RGW bucket resharding. Its two-phase architecture moves intensive work into a non-blocking background phase, avoiding the prolonged write unavailability and 504 errors seen in Ceph Squid and earlier versions.

## Source excerpt

Introduction: The Foundation of Scalable Object Storage ¶ In the modern data landscape, object storage has evolved from a simple file repository into the foundational layer for AI/ML pipelines, data lakehouses, real-time analytics, and massive-scale archival systems. At the heart of this evolution is a deceptively simple question: How do you efficiently locate and access billions of objects stored in a single bucket? The answer lies in one of Ceph's most critical performance mechanisms: bucket index sharding. This architectural pattern divides a bucket's index into multiple parallel structures, enabling concurrent operations across thousands of objects while maintaining the consistency and reliability that enterprise workloads demand. But there's always been a catch. As workloads grow and evolve, buckets need to be resharded. Historically, when the buckets to be resharded had a vast number of objects, this operation came with a painful trade-off: blocking client writes from seconds to minutes, with a chance of causing application disruptions, 504 Gateway errors, and operational headaches. With Ceph Tentacle, we're eliminating this trade-off. The new near-zero impact bucket resharding architecture transforms what was once a maintenance window event into a seamless background operation that your applications will never notice. Note: As of 2026/02/05, the functionality described in this article is expected in an upcoming Tentacle update. Executive Summary ¶ The Challenge: In Ceph Squid, resharding a 20-million-object bucket blocked writes for 4+ minutes, returning 504 errors. Even larger buckets (500M objects) required 94 minutes of complete write unavailability. The Solution: Ceph Tentacle's two-phase architecture moves the heavy lifting to a non-blocking background phase, eliminating the impact on clients IO. The Results: (note: in this graphic 8.1 refers to Squid and 9.0 to Tentacle) In this deep dive, we'll explore: Why bucket sharding is essential for modern workl