Computational Storage - Delta Chain for updatable objects in Ox

Delta Chains in OX
Students: Alexander Palsson, Benjamin Møller Noer & Mark Kristian Kristensen
Supervisor: Philippe Bonnet
Level: BSc, Semester: Spring 2020
Tags: SSDs, OX, Computational Storage

One of the limitations to Ox Block is that everything has to be aligned to the sector size on the SSD, 4 kb. Another limitation is that in place updated are not allowed on SSD’s in general, but using an entire erase and write cycle might be wasteful if the update is minimal. A solution to both of these problems would be to implement a system that manages the difference in an update to an already written page. An idea for this system is a so called delta chain, that keeps track of the difference in updates to a page and stores them as deltas. Then it only writes to the original page at a convenient time. There is an abundance of questions that need to be answered before such a system can be implemented. Some of those questions are: • What is a delta? • How is a delta stored? • When is the delta chain applied to the original page? • How is the delta chain applied to the original page?