$ show Open-CAS/open-cas-linux
Open CAS Linux is a production-grade block-layer cache acceleration solution for Linux. It consists of a kernel module (`cas_cache`) implementing caching logic on top of the OCF (Open Cache Framework), a block device module (`cas_bd`), and a user-space management CLI (`casadm`). The system accelerates block I/O by caching hot data on fast storage (e.g., NVMe/Optane) while using slower backing storage, with support for multiple cache modes, cleaning policies, I/O classes, and statistics reporting. Management is performed via ioctls through `/dev/cas_ctrl` and netlink-based communication, with a comprehensive CLI (`casadm`) for cache/core lifecycle operations and statistics output in text, CSV, and raw CSV formats.
The LLM identified 3 files worth highlighting for reuse:
Implements a view abstraction that renders an intermediate tag-based format (KV_PAIR, TABLE_ROW, etc.) to text, CSV, or raw CSV output. The vtable-like `view_t` design is self-contained and could be extracted for any tool needing pluggable output formatters.
Demonstrates a robust kernel-userspace netlink dump pattern: data is pre-collected under a read lock, then emitted as multiple NLM_F_MULTI messages per cache (cache record, core records, ioclass records). This is a reusable pattern for implementing scalable, lock-safe netlink dump interfaces.
Provides a parallel sorting utility for large statistics datasets. It is isolated enough to be reused in other performance-oriented user-space tools that need to sort large in-memory records efficiently.