# osd Published articles for osd. This is one page of public article previews, not the complete archive. Follow Next page to continue. Summaries are not the original full articles. ## v20.2.1 Tentacle released DevFeed: [v20.2.1 Tentacle released]() Original publisher: [Read original article]() Author: Yuri Weinstein Published: 2026-04-06T00:00:00Z Content type: release Language: en Sources: [Ceph Blog]() Topics: [bug](), [configuration](), [monitor](), [Command-line interface](), [API](), [dashboards](), [JSON]() Tags: [2026](), [api](), [blog-post](), [bug](), [cli](), [en-article](), [en-blog-post](), [json](), [monitor](), [nvme](), [osd](), [peering](), [policy](), [recovery](), [reef](), [release](), [rgw](), [tentacle](), [ui](), [workflows]() ### AI overview Ceph v20.2.1, the first minor release in the Tentacle series, is recommended for all users. The release fixes storage, recovery, peering, validation, and dashboard issues; restricts unsafe fast EC configurations; improves NVMeoF Gateway failover; adds listener and subsystem CLI commands; introduces a transient exclusive RBD lock policy; and updates dashboard navigation and forms. ### Source excerpt This is the first minor release in the Tentacle series. We recommend that all users update to this release. Release Date ¶ April 06, 2026 Notable Changes ¶ OSD / BlueStore ¶ EC Recovery: Fixed a length calculation bug in erase_after_ro_offset() that caused empty shards to retain data, leading to shard_size >= tobj_size assertion failures when recovering small objects in EC pools. BlueFS Volume Selector: Updated the BlueFS volume selector to properly account for file size changes when recovering the WAL in envelope mode. BlueFS: Fixed a bug where stat() missed the actual file size update after indexing WAL envelope files. Monitor (mon) ¶ Fast EC Restrictions: Denied the ability to enable EC optimizations ("fast EC") for non-4K-aligned chunk sizes. Unaligned chunk sizes handled by fast EC perform poorly and suffer from bugs, so attempts to force this configuration are now rejected. Peering: Ensured ceph pg repeer proposes a correctly sized pg temp, as optimized EC cannot cope with mismatched sizes. NVMeoF Gateway: Added a new nvme-gw listeners command to display all existing listeners (including auto-listeners) inside a pool/group. NVMeoF Failover: Overhauled the NVMeoF Gateway fast-failover logic. Beacon timeouts are now evaluated within prepare_beacon to support shorter intervals, and the mechanism for detecting monitor slowness was improved. librbd & rbd-mirror ¶ RBD: Introduced a new RBD_LOCK_MODE_EXCLUSIVE_TRANSIENT policy for rbd_lock_acquire(). This is a low-level interface intended to allow a peer to grab exclusive lock manually for short periods of time with other peers pausing their activity and waiting for the lock to be released rather than instantly aborting I/O and returning an error. It's possible to switch from RBD_LOCK_MODE_EXCLUSIVE to RBD_LOCK_MODE_EXCLUSIVE_TRANSIENT policy and vice versa even if the lock is already held. Ceph Object Gateway (RGW) ¶ Multi-Part Operations: Fixed conditional validation handling in MultiWrite, Delete, and MultiDelete ## RocksDB Compression in Ceph: Space Savings with No Performance Cost DevFeed: [RocksDB Compression in Ceph: Space Savings with No Performance Cost]() Original publisher: [Read original article]() Author: Daniel Alexander Parkes, Anthony D'Atri Published: 2025-12-17T00:00:00Z Content type: article Language: en Sources: [Ceph Blog]() Topics: [Compression](), [Database](), [Hardware](), [ibm]() Tags: [blog-post](), [ceph](), [compression](), [configuration](), [cost](), [devices](), [en-article](), [en-blog-post](), [ibm](), [mon](), [nvme](), [osd](), [performance](), [rados](), [reef](), [rocksdb](), [space](), [storage]() ### AI overview This article reports Ceph performance tests showing that enabling RocksDB compression can substantially reduce metadata database space, especially for smaller objects, without harming throughput or resource consumption. The tests used IBM Storage Ceph 7.1 with BlueStore OSDs, HDD object storage, and NVMe devices for the RocksDB WAL and database. ### Source excerpt Introduction ¶ In the world of data storage, engineers and architects constantly face a fundamental dilemma: the trade-off between performance and efficiency. It's a balancing act. When you want to save space, you typically enable features like compression, but the common assumption is that this will cost you performance, a CPU cycle tax that slows throughput. But what if you could significantly reduce your metadata storage footprint without slowing things down? This search for an answer to this question started with research work from Mark Nelson, who published a blog post on ceph.io that covers RocksDB tuning in depth, exploring RocksDB compression with positive results. These promising results sparked a conversation on the upstream GitHub about enabling compression by default; a link to the PR is available here. To build on the previous investigation, the Ceph performance team ran tests on a robust hardware configuration running IBM Storage Ceph 7.1 (Reef). The cluster used the BlueStore OSDs for an erasure-coded (EC 4+2) pool, with a hybrid OSD storage setup: HDDs for object data and fast NVMe drives for the BlueStore WAL+DB. To understand the test, it's helpful to know what the WAL+DB is. In modern Ceph, the BlueStore storage engine manages all data on the OSDs (physical devices). To do this, it must maintain a vast catalog of internal metadata: think of it as a high-speed index that quickly locates every piece of data. RocksDB, a high-performance key-value database, manages this critical index. In our hybrid cluster, the RocksDB database runs on the fast NVMe deviceses, while the actual object data resides on the slower HDDs. Because this metadata can grow very large, RocksDB's efficiency, how much space it consumes on those expensive NVMe drives, is a critical factor in the cluster's overall cost and performance. Our test, therefore, focuses on a simple, high-stakes question: Can we compress this metadata to save space without paying a performance penalty? Ex