Define a high level plan for remote search index

[anasalkouz]

The goal of this issue is to consolidate the open issues around the "writable remote index" work and define the first pieces we will incrementally deliver toward this end. The main open issues are:

• [Feature Proposal] Writable Remote Index #7804 (high level feature proposal)
• [Draft][RFC] Multi-tiered file cache #8891 (design for a critical component of the potential solution)
• [Meta] Remote store-based warm index #8446 (some initial prototyping/proof-of-concept design and code)

Issue #8891 and #9987 will track the work to implement the core logic of the directory to provide the "writeable warm" semantics. This issue is a plan that proposes a basic breakdown of other components that can happen in parallel and allow us to start chipping away at this effort incrementally:

• Introduce a new feature flag on main to gate this functionality
• Introduce a new index setting/property for toggling a remote store index as "writable warm"
• TODO: add task(s) that come from [Discuss] Design for Tiered File Cache & Block Level fetch #9987
• Implement remote store-based on-demand block-based fetching directory

[rakeshrauniyar12]

can you describe that what exactly we have to do ???

[anasalkouz]

Sure, @andrross will provide more details by next week

[andrross]

Resolving as sub issues have been created