Block management in solid state devices ebook download pdf
Solid-state devices (SSDs) have the potential to replace traditional hard disk drives (HDDs) as the de facto storage medium. Unfortunately, there are several decades of spinning-media assumptions embedded in the software stack as an “unwritten contract” . In this paper, we revisit these system-level assumptions in light of SSDs and find that several of them are invalidated by SSDs, breaking the unwritten contract and resulting in poor performance and lifetime. The underlying cause is the incorrect division of labor between file systems and storage. Block management must be removed from the file system and delegated to the SSD to prevent further accumulation of storage-specific assumptions. We find that object-based storage is an appropriate way to achieve this.