Overlay disks

[yulikdaniel]

Changelog category (leave one):

• New Feature

Changelog entry (a user-readable short description of the changes that goes to CHANGELOG.md):

Add overlay disks, disks that are initialized from a read-only disk with the initial state and a read-write disk where the diff is stored. No data is copied.

Documentation entry for user-facing changes

• Documentation is written (mandatory for new features)

Information about CI checks: https://clickhouse.com/docs/en/development/continuous-integration/

Modify your CI run

NOTE: If your merge the PR with modified CI you MUST KNOW what you are doing
NOTE: Checked options will be applied if set before CI RunConfig/PrepareRunConfig step

Include tests (required builds will be added automatically):

• Fast test
• Integration Tests
• Stateless tests
• Stateful tests
• Unit tests
• Performance tests
• All with ASAN
• All with TSAN
• All with Analyzer
• All with Azure
• Add your option here

Exclude tests:

• Fast test
• Integration Tests
• Stateless tests
• Stateful tests
• Performance tests
• All with ASAN
• All with TSAN
• All with MSAN
• All with UBSAN
• All with Coverage
• All with Aarch64
• Add your option here

Extra options:

• do not test (only style check)
• disable merge-commit (no merge from master before tests)
• disable CI cache (job reuse)

Only specified batches in multi-batch jobs:

• 1
• 2
• 3
• 4

[CLAassistant]

All committers have signed the CLA.

[robot-ch-test-poll2]

This is an automated comment for commit 0af0fda with description of existing statuses. It's updated for the latest CI running

❌ Click here to open a full report in a separate page

Check name	Description	Status
CI running	A meta-check that indicates the running CI. Normally, it's in success or pending state. The failed status indicates some problems with the PR	⏳ pending
ClickHouse build check	Builds ClickHouse in various configurations for use in further steps. You have to fix the builds that fail. Build logs often has enough information to fix the error, but you might have to reproduce the failure locally. The cmake options can be found in the build log, grepping for cmake. Use these options and follow the general build process	⏳ pending
Mergeable Check	Checks if all other necessary checks are successful	❌ failure
Style check	Runs a set of checks to keep the code style clean. If some of tests failed, see the related log from the report	❌ failure

Successful checks

Check name	Description	Status
Docs check	Builds and tests the documentation	✅ success
PR Check	There's no description for the check yet, please add it to tests/ci/ci_config.py:CHECK_DESCRIPTIONS	✅ success