The complexity of block I/O caching is detailed in this article, delving into the importance of understanding I/O profiles. The use of Solid State Drives (SSDs) as caches for slower HDDs is highlighted, aiming to bridge the performance gap. Various caching methods like writeback, write-through, and write-around are discussed, with solutions like dm-writecache, bcache, and dm-cache explored. A step-by-step guide on configuring caching environments using logical volume manager (LVM2) and practical benchmarking demonstrates the impact of caching. Unique tools such as RapidDisk, Memcached, and ReadyBoost offer additional insights, providing a comprehensive overview of I/O caching on Linux systems.
https://www.admin-magazine.com/HPC/Articles/Linux-Writecache