make storage balancer async and turned on

[vporyadke]

Changelog entry

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Changelog category

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Description for reviewers

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[CyberROFL]

@vporyadke привяжи issue

[Copilot]

Pull Request Overview

This PR enables the storage balancer by default and makes storage reassignment operations asynchronous to improve performance. The key changes include:

• Updated storage balancer configuration defaults to enable balancing by default
• Made storage balancer reassignments asynchronous
• Updated tests to force synchronous reassignments for deterministic behavior

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 1 comment.

File	Description
ydb/core/protos/config.proto	Changed default values to enable storage balancer (MinStorageScatterToBalance: 999→0.5, MinGroupUsageToBalance: 0.1→0.05, MaxChannelHistorySize: 200→10)
ydb/core/mind/hive/storage_balancer.cpp	Made reassignment operations asynchronous by setting Async flag to true
ydb/core/mind/hive/hive_ut.cpp	Added test observers to override async reassignments to synchronous for deterministic test execution

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[github-actions]

🟢 2025-11-05 12:18:22 UTC The validation of the Pull Request description is successful.

[github-actions]

⚪ 2025-11-05 13:30:24 UTC Pre-commit check linux-x86_64-relwithdebinfo for f8dc19b has started.
⚪ 2025-11-05 13:30:43 UTC Artifacts will be uploaded here
⚪ 2025-11-05 13:32:18 UTC ya make is running...
🟡 2025-11-05 15:45:40 UTC Some tests failed, follow the links below. Going to retry failed tests...

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
41560	38717	0	1	2810	32

⚪ 2025-11-05 15:45:52 UTC ya make is running... (failed tests rerun, try 2)
🟢 2025-11-05 15:59:34 UTC Tests successful.

Ya make output | Test bloat | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
85 (only retried tests)	65	0	0	0	20

🟢 2025-11-05 15:59:37 UTC Build successful.
🟢 2025-11-05 15:59:53 UTC ydbd size 2.3 GiB changed* by +96 Bytes, which is < 100.0 KiB vs main: OK

ydbd size dash	main: fac5e44	merge: f8dc19b	diff	diff %
ydbd size	2 429 618 744 Bytes	2 429 618 840 Bytes	+96 Bytes	+0.000%
ydbd stripped size	516 186 664 Bytes	516 186 664 Bytes	0 Bytes	0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}

[github-actions]

⚪ 2025-11-05 13:34:37 UTC Pre-commit check linux-x86_64-release-asan for f8dc19b has started.
⚪ 2025-11-05 13:34:53 UTC Artifacts will be uploaded here
⚪ 2025-11-05 13:36:16 UTC ya make is running...
🟡 2025-11-05 16:16:28 UTC Some tests failed, follow the links below. This fail is not in blocking policy yet

Ya make output | Test bloat

TESTS	PASSED	ERRORS	FAILED	SKIPPED	MUTED?
18094	17683	0	165	219	27

🟢 2025-11-05 16:16:36 UTC Build successful.
🟢 2025-11-05 16:17:00 UTC ydbd size 3.8 GiB changed* by +160 Bytes, which is < 100.0 KiB vs main: OK

ydbd size dash	main: fac5e44	merge: f8dc19b	diff	diff %
ydbd size	4 069 308 256 Bytes	4 069 308 416 Bytes	+160 Bytes	+0.000%
ydbd stripped size	1 510 632 040 Bytes	1 510 632 104 Bytes	+64 Bytes	+0.000%

^{*please be aware that the difference is based on comparing your commit and the last completed build from the post-commit, check comparation}