May 2026 performance summary for ydb-platform/nbs: Delivered critical reliability and concurrency improvements focused on secure erase workflows and request handling during migrations. Key features include a configurable cooldown before secure erasing devices to prevent race conditions with late requests from destroyed volumes, and integration of a restartable sequences framework to improve concurrency and reliability. Major bug fixes addressed error propagation in split requests and tightened error handling for synchronous responses after splits. Collectively, these changes reduce migration failures, improve safe erase operations, and enhance system stability in production environments. Technologies demonstrated include librseq integration, atomic BlockSize handling, base-class accessors for BlockSize, and robust concurrency patterns. Business value: lower migration risk, safer device erasures, and stronger user experience due to fewer failures and clearer error handling.

In April 2026, contributed to ydb-platform/nbs with four focused improvements: two bug fixes enhancing session management reliability, one robustness enhancement for volume creation, and two feature-level improvements (profile log analytics and Abseil data structures). The changes reduced test flakiness with TSAN, improved provisioning reliability by refining the volume copy script, provided more accurate event logging metrics for profiling, and introduced efficient Abseil btree_map/btree_set. Business impact: higher CI stability, fewer provisioning failures, better performance visibility, and more scalable container performance.

March 2026 performance summary: Achieved meaningful performance and reliability gains in storage I/O and request orchestration across ydb-platform/nbs and ydb-platform/ydb. In NBS, released block storage range handling and I/O enhancements enabling sub-range access, stripe-based block range splitting, and improved read/write/zero request helpers; introduced overlapping request handling policy and a request-splitting service to boost concurrency; and completed code-quality and dependency-management improvements to Arcadia sync. In YDB, implemented large-block storage request splitting to enhance throughput at scale; advanced persistent buffers synchronization and asynchronous I/O with refactored read/write paths and futures; and reorganized protobufs into a dedicated protos directory with updated build paths for external integrations. Notable fixes include reading from encrypted local disks with multiple buffers and build-sync fixes for Arcadia. Overall impact: improved data integrity, throughput, and scalability, reduced contention, and more reliable cross-repo builds, delivering business value in storage performance, reliability, and developer productivity.

February 2026 (2026-02) performance and reliability highlights across ydb-platform/ydb and ydb-platform/nbs. Delivered features, fixes, and maintenance that improve maintainability, reliability, observability, and business value in storage workflows. Key contributions spanned large-scale codebase hygiene, storage reliability improvements, Linux service readiness, and richer volume metadata workflows across two repos.

January 2026 monthly summary focusing on key accomplishments across ydb-platform/nbs and ydb platform. Highlights include delivering multi-partition volume support, RDMA request management optimization, storage reliability and security enhancements, path backup format improvements, and build/test/quality improvements; plus NBS scaffolding, vhost-user protocol library, CPU affinity and memory buffers management. A critical bug fix corrected local SSD max blocks calculation using 512-byte blocks. Overall impact: improved scalability, performance, observability, security, and deployment hygiene.

December 2025 monthly summary for ydb-platform/nbs focused on reliability, performance, and measurable business value across storage backends. The team delivered new data analytics capabilities, improved range management, IO visibility, and code quality, with several stability fixes to prevent regressions in production. Key features delivered: - Zero-block statistics across block ranges with per-disk zero-ranges ratio calculations and a JSON export path for easy integration. - New block-range utilities (TBlockRangeList and TBlockRangeMap) and refactored requests-in-progress tracking to unify inflight stats and speed up overlap detection. - IO distribution and IO-load analytics, including optimized reads from mirrors and first-device IO-load profiling, enabling better capacity planning and fault diagnosis. - Metrics and observability improvements: migrated metrics to logical disk IDs, agent-level latency tracking for DiskRegistry devices, and enhanced logging in the shadow disk actor. - Build quality and maintenance: clang-format tuning, tabs-to-spaces, separation of JS/CSS into resource files, and targeted build fixes to improve CI reliability. Major bugs fixed (highlights): - Ignored time tracking events when DiskRegistry is in zombie state to avoid distorted metrics. - Fixed crash on double registration of the same diskId in TStatsServiceActor and addressed use-after-free in related tests. - Fixed undelivery handling in multi-agent writes discovery requests and improved multi-partition request stability. - Resolved open_close_bench build issues and ensured compatibility with arcadia/test environments. Overall impact and accomplishments: - Stronger data integrity and observability enabled by new statistics, improved overlap checks, and consistent metrics naming. - Performance-focused optimizations reduced CPU usage and improved IO visibility for capacity planning and fault isolation. - Higher code quality and CI stability through formatting standards and build fixes. Technologies/skills demonstrated: - C++, range query structures, and refactoring patterns (TBlockRangeList/Map, inflight tracking). - IO profiling, performance measurement, and capacity planning analytics. - Observability stack improvements (metrics, latency tracking, enriched logging). - Code quality, test stability, and build engineering (clang-format, Arcadia compatibility, resource management).

2025-11 Monthly Summary for ydb-platform/nbs: Macro-to-template migration across the codebase (Parts 1–4) replacing macros with template methods to improve safety and maintainability. Live migration to the new leader volume enabling near-zero downtime and seamless session switching. Observability and tracing enhancements: added x-request-id header for KMS requests; improved logging for unexpected events; unified inflight DiskRegistry telemetry. Architecture/config improvements: centralized device operation ID generation in TDeviceOperationTracker; VolumeActorId propagation to the RDMA actor; unified device index naming in partition config; helper extraction to collect all devices of a volume. Reliability and stability improvements: fixed crash in NBlockStore NClient; zombie-state shutdown safeguards to ignore messages during shutdown; resolved Arcadia lint/build issues. Overall, the month delivered substantial code health improvements, improved traceability, and a stronger foundation for scalable and reliable operation.

October 2025, ydb-platform/nbs: Implemented robust leadership transfer for block storage volumes with state synchronization and safe client switchover, reducing downtime during leadership changes. Introduced LeadershipTransferred state, request gating, and lifecycle hooks (BeforeSwitching/AfterSwitching) to enable safe, controlled client switches. Enhanced data integrity and diagnostics by adding per-block checksums to profile logs and persisting profiling events in SQLite. Added chaos testing for DiskAgent to simulate errors and resilience, and migrated volume_label.* to model to decouple dependencies and speed builds. Analytics enhancements and stabilization fixes were also delivered to improve maintainability and traceability. Business value: higher reliability, faster diagnostics, and safer deployment cycles.

In September 2025, the NBS initiative delivered a cohesive set of features that improve reliability, uptime, and observability for disk management and runtime operations within ydb-platform/nbs. The work emphasizes safer disk copy workflows, zero-downtime switchovers, and improved monitoring and diagnostics, translating into tangible business value through safer data handling, reduced maintenance windows, and clearer operator visibility.

August 2025 Monthly Summary for ydb-platform/nbs: Focused on delivering robust partitioned volume operations, reliable follower data migration, and expanded testing coverage to accelerate safe deployment of linked volumes and cross-host tablet migration. Emphasized code quality, build stability, and CI reliability to shorten feedback cycles and reduce risk in production rollouts.

July 2025 (2025-07) monthly summary for ydb-platform/nbs. Focused on delivering reliable infrastructure improvements, meaningful feature enhancements, and targeted fixes that reduce operational risk, accelerate development, and improve data consistency across replicas.

In June 2025, the NBS team advanced observability, reliability, and performance for the DiskRegistry and volume management stack. Delivered features include: latency metrics visibility on the DiskRegistry monitoring page to support performance analysis; comprehensive observability and logging enhancements across components (new log titles, richer context such as diskId, tabletId, session and client details, startup/shutdown events) to improve traceability; volume link propagation between leader and follower volumes with new messaging and state-management improvements; a Hybrid Write Strategy for non-replicated partitions to optimize throughput while preserving data consistency; and build/test stability and infrastructure improvements (replacing deprecated code, updating build events, enabling multi-volume test support and new image/test infrastructure).

May 2025 summary for ydb-platform/nbs focusing on reliability, observability, and multi-agent workloads. Delivered features to improve error messaging, enable multi-agent messaging with RDMA, and enhanced latency/monitoring UI, while stabilizing builds and configurations for production readiness.

April 2025 monthly summary for ydb-platform/nbs focusing on migration robustness, partition management, enhanced I/O, reliability, and observability. Delivered a set of features and improvements that increase resilience, scalability, and operational efficiency, with strong business value in safer migrations, safer and more scalable partition workflows, and improved debugging and monitoring.

March 2025 (2025-03) monthly summary for ydb-platform/nbs. Delivered features focused on reliability, data consistency, and developer experience, enabling safer cross-disk volume management and stronger data repair capabilities while tightening build quality and diagnostics.

February 2025: Delivered core platform enhancements in ydb-platform/nbs with a focus on performance benchmarking, data integrity, and internal reliability. The work enables robust performance analysis, safer write operations across mirrored storage, and a more maintainable codebase and build/test process, accelerating future iterations and reducing risk in production releases.

January 2025 (2025-01) - Delivered several high-impact features and reliability improvements in ydb-platform/nbs, with a focus on operational usability, performance testing, and stability. Implemented Disk Registry Benchmarking Infrastructure to simulate real workloads, added Bandwidth Throttling and a bandwidth calculator to optimize resource use, and exposed direct device/agent state controls in Monpage for easier management. Strengthened reliability with Shadow Disk reacquisition robustness and correct state transitions, and ensured HW_PROBLEMS flag preservation on silent I/O errors. Completed extensive maintenance (build, lint, docs, tests) to boost stability and developer velocity. These investments enable better capacity planning, faster issue detection, and safer, more controllable production systems.

December 2024 focused on stabilizing and accelerating disk copy workflows in ydb-platform/nbs, delivering a robust DirectCopy path, improving observability, and cleaning up the build and ownership model. Key outcomes include a new DiskAgent DirectCopyBlocks flow with range-based device mapping, GetDeviceForRange support, and harmonized DiskAgent/ActorId notifications, plus migrating TDirectCopyActor to its own source file and wiring DirectCopy in related contexts. DirectBlockCopy statistics were added to improve monitoring. Parallel work enhanced error reporting and CI reliability through a series of fixes and cleanups: always augment error flags, test flakiness fixes, use-after-free remediation, Arcadia sync corrections, and reachability improvements. Build hygiene was improved via cleanup commits (removing unused params, consistent TBlockRange printing, typo fixes, and ya.make ownership simplification). Overall, these changes reduce operational risk, shorten data migration and replication cycles, and improve diagnosability and maintainability.

November 2024 performance summary for ydb-platform/nbs. Key work focused on delivering a memory-safe, performant data transfer workflow, stabilizing core data paths, and laying groundwork for maintainable long-term reliability. Highlights include: 1) Drove feature delivery with comprehensive documentation for Direct data copying between disk agents, including design overview and sequence diagrams to clarify efficient transfer and reduced network usage. 2) Fixed critical bugs that improve correctness and stability: Encrypted volumes now use volumeRequestId for requests (with updated unit tests for both encrypted and non-encrypted scenarios) and TString buffer access fixed in the VFS fuse layer to ensure proper memory handling. 3) Initiated and completed a major internal refactor for non-replicated partition handling, introducing a base request actor, granular timeout policy, and lifecycle improvements across shadow/partition actors, with lint and test scaffolding to reduce regressions. These efforts collectively enhance data transfer efficiency, reliability of encrypted workflows, and maintainability of the partition-handling stack. 4) Demonstrated strong technical breadth across C++ system programming, actor-model designs, VFS integration, test coverage, and documentation/diagrams for onboarding and knowledge sharing.