Designing multicore scalable filesystems with durability and crash consistency

It is challenging to simultaneously achieve multicore scalability and high disk throughput in a file system. For example, data structures that are on separate cache lines in memory (e.g., directory entries) are grouped together in a transaction log when the file system writes them to disk. This grouping results in cache line conflicts, thereby limiting scalability. McoreFS is a novel file system design that decouples the in-memory file system from the on-disk file system using per-core operation logs. This design facilitates the use of highly concurrent data structures for the in-memory representation, which allows commutative operations to proceed without conflicts and hence scale perfectly. McoreFS logs operations in a per-core log so that it can delay propagating updates to the disk representation until an fsync. The fsync call merges the per-core logs and applies the operations to disk. McoreFS uses several techniques to perform the merge correctly while achieving good performance: timestamped linearization points to order updates without introducing cache line conflicts, absorption of logged operations, and dependency tracking across operations. Experiments with a prototype of McoreFS show that its implementation is conflict-free for 99% of test cases involving commutative operations generated by Commuter, scales well on an 80-core machine, and provides disk performance that matches or exceeds that of Linux ext4.

Department dc:contributor.department

Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science.

Grantor dc:publisher

Massachusetts Institute of Technology

Year dc:date.issued

2017

Author dc:creator

• Bhat, Srivatsa S. (Srivatsa Sitaram)

Advisor dc:contributor.advisor

• M. Frans Kaashoek and Nickolai Zeldovich.

• Electrical Engineering and Computer Science.

Statement dc:rights

• MIT theses are protected by copyright. They may be viewed, downloaded, or printed from this source but further reproduction or distribution in any format is prohibited without written permission.

Licence dc:rights.uri

• http://dspace.mit.edu/handle/1721.1/7582

Language dc:language.iso

eng

Handle dc:identifier.uri

http://hdl.handle.net/1721.1/111864

OAI identifier oai:identifier

oai:dspace.mit.edu:1721.1/111864