Vault 2015

While it has yet to claim as many years of expected imminent arrival, an I/O cache hinting solution for Linux has been under serious consideration since at least LSF 2012. All the major storage interface standards bodies (NFS, T10, T13, and NVME working groups) have each defined cache attributes that can be specified in their respective transports. Perhaps the largest hurdle to overcome for this effort is finding the minimal set of hints that unlocks the bulk of the potential of capable devices without committing the Linux kernel to maintaining an overly complicated hinting framework. This presentation seeks to stand on the foundation of Martin Petersen’s work in this space (wrangling device hinting schemes vs fadvise() in the kernel) and reconcile it with learnings from the Intel effort to implement support for T13/SATA-IO hints in current Solid State Hybrid Drives (SSHDs).