Hierarchical Storage Management
The CloudTier Storage Tiering Filter Driver SDK is a Hierarchical Storage Management (HSM) development kit. It provides a kernel-level framework to implement transparent data migration between high-cost (hot) and low-cost (cold) storage media. By replacing migrated files with Stub Files, it enables organizations to optimize storage efficiency and reduce OpEx/CapEx without disrupting existing applications. System Architecture The SDK operates at the file system filter level, acting as an "invisible traffic cop" between user applications and the Windows NTFS/ReFS file system. Kernel-Mode Filter Driver: Intercepts I/O requests (IRP_MJ_READ, IRP_MJ_CREATE) and manages reparse points. It evaluates requests against business rules to determine if data resides locally or requires a remote fetch. User-Mode Service (Policy & Logic): Manages cloud connectivity (S3, Azure, etc.) and executes the Lifecycle Management policies. Stub Management: Leverages Windows reparse po...