LVM recently introduced a second form of caching focused on improving write performance to a volume. LVM has previously supported a "hot spot" cache that is used for both reading and writing. The hot spot cache (using the dm-cache kernel component) adjusts cache content over time so that the most used parts of a volume are kept on a faster device. With the new writecache feature (using the dm-writecache kernel component), all writes go to a faster device (PMEM or SSD) prior to being written to the slower primary device. The writecache is especially beneficial for programs like databases where low commit latency is needed. The session will describe the differences between the two forms of caching, and demonstrate how to configure each using LVM. Attendees should be familiar with basic LVM terms and usage.
Friday January 24, 2020 5:30pm - 5:55pm CET
A113Faculty of Information Technology Brno University of Technology, Božetěchova, Brno-Královo Pole, Czechia
