Ramnatthan Alagappan

Postdoctoral Researcher
VMware Research Group
Ph.D. University of Wisconsin - Madison
Email: ralagappan@vmware.com, ra@cs.wisc.edu
CV | Google Scholar | DBLP

I am on the academic job market. Please reach out to me if you are hiring!

Materials: CV, Statements (Research, Teaching, Diversity)

Upcoming Talks
University of Waterloo, Jan 20-21
Virginia Tech, Date TBF

About Me: I am a postdoctoral researcher at VMware Research Group. I earned my Ph.D. working with Prof. Andrea Arpaci-Dusseau and Prof. Remzi Arpaci-Dusseau at Wisconsin CS. I am a computer systems researcher. My research focuses on building systems that offer improved reliability and deliver high performance. I combine expertise from operating systems, storage, and distributed computing to design new reliability measures and exploit performance opportunities in these systems. My dissertation explores reliability and performance problems at the storage interface in distributed systems.

My research has had both academic and industrial impact. My work has been published at premier systems venues (SOSP, OSDI, FAST, EuroSys, and ATC), invited to journals (CACM and TOS), and has won three best paper awards. Frameworks I developed have had a significant practical impact: they have exposed more than 80 serious bugs across 20 different widely used systems. Ideas from these tools have also influenced popular testing tools. The CTRL protocol introduced in my FAST ’18 paper has been adopted by a commercial replicated database to make it resilient to storage faults. My work has also been discussed widely in popular research and developer forums.



Awards

Research

Best Paper FAST '20 - CAD
UW CS Graduate Student Research (Best Dissertation Research) Award - Honorable Mention - 2019
Best Paper FAST '18 - PAR/CTRL
Best Paper FAST '17 - CCFS
Best Paper Nominee FAST '17- Redundancy Does Not Imply Fault Tolerance

Teaching

CS 739 ranked 1st among all Spring 20 courses in student evaluations
Nominated for SACM CoW Teaching Award for CS 739

Service

Distinguished Reviewer HotStorage - 2021
Best Shadow PC Reviewer Eurosys '19

Grants and Scholarships

MS Azure Credits Research Award for $50,000 - 2019
Facebook Distributed Systems Research Award for $50,000 - 2019
Alumni Scholarship, UW Madison - 2013

Publications

[Peer-Reviewed Conference] [Peer-Reviewed Workshop] [Peer-Reviewed Journal & Invited]

Peer-Reviewed Conference Publications


Exploiting Nil-Externality for Fast Replicated Storage
Aishwarya Ganesan, Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
28th ACM Symposium on Operating Systems Principles
PDF, BibTex, Talk Slides, Video - short, Video - long, Code
Invited to Transactions on Storage
SOSP '21
The Storage Hierarchy is Not a Hierarchy: Optimizing Caching on Modern Storage Devices with Orthus
Kan Wu, Zhihan Guo, Guanzhou Hu, Kaiwei Tu, Ramnatthan Alagappan, Rathijit Sen, Kwanghyun Park, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
19th USENIX Conference on File and Storage Technologies
PDF
FAST '21
From Wisckey to Bourbon: A Learned Index for Log-structured Merge Trees
Yifan Dai, Yien Xu, Aishwarya Ganesan, Ramnatthan Alagappan, Brian Kroth, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Proceedings of the 14th Symposium on Operating System and Design Implementation
PDF, BibTex
OSDI '20
Can Applications Recover from fsync Failures?
Anthony Rebello, Yuvraj Patel, Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
The 2020 USENIX Annual Technical Conference
PDF, BibTex
Invited to Transactions on Storage
ATC '20
Strong and Efficient Consistency with Consistency-aware Durability
Aishwarya Ganesan, Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
18th USENIX Conference on File and Storage Technologies
PDF, BibTex, Talk Slides
Best Paper Award
Invited to Transactions on Storage
FAST '20
Fault-Tolerance, Fast and Slow: Exploiting Failure Asynchrony in Distributed Systems
Ramnatthan Alagappan, Aishwarya Ganesan, Jing Liu, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Proceedings of the 13th Symposium on Operating System and Design Implementation
PDF, BibTex, Talk Slides
OSDI '18
Protocol-Aware Recovery for Consensus-Based Storage
Ramnatthan Alagappan, Aishwarya Ganesan, Eric Lee, Aws Albarghouthi, Vijay Chidambaram, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Proceedings of the 16th USENIX Conference on File and Storage Technologies
PDF, BibTex, Talk Slides
Best Paper Award
Invited to Transactions on Storage
Invited to ATC 19 Best of the Rest
Coverage: Morning Paper, zdnet
FAST '18
Atomic In-Place Updates for Non-Volatile Main Memories with KaminoTx
Amir Saman Memaripour, Anirudh Badam, Amar Phanishayee, Yanqi Zhou, Ramnatthan Alagappan, Karin Strauss, Steven Swanson
Proceedings of the Twelfth European Conference on Computer Systems
PDF, BibTex
EuroSys '17
Redundancy Does Not Imply Fault Tolerance: Analysis of Distributed Storage Reactions to Single Errors and Corruptions
Aishwarya Ganesan, Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Proceedings of the 15th USENIX Conference on File and Storage Technologies
PDF, BibTex, Talk Slides, Project, Code
Best Paper Award Nominee
Invited to Transactions on Storage
Invited to Usenix ;login:
Coverage: StorageMojo, Morning Paper, DHSR's blog
FAST '17
Application Crash Consistency and Performance with C2FS
Thanumalayan Sankaranarayana Pillai, Ramnatthan Alagappan, Lanyue Lu, Vijay Chidambaram, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Proceedings of the 15th USENIX Conference on File and Storage Technologies
PDF, BibTex, Talk Slides
Best Paper Award
Invited to Transactions on Storage
Invited to ATC 18 Best of the Rest
Coverage: Morning Paper
FAST '17
Correlated Crash Vulnerabilities
Ramnatthan Alagappan, Aishwarya Ganesan, Yuvraj Patel, Thanumalayan Sankaranarayana Pillai, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Proceedings of the 12th Symposium on Operating System and Design Implementation
PDF, BibTex, Project, Talk Slides, Code
OSDI '16
All File Systems Are Not Created Equal: On the Complexity of Crafting Crash-Consistent Applications
Thanumalayan Sankaranarayana Pillai, Vijay Chidambaram, Ramnatthan Alagappan, Samer Al Kiswany, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Proceedings of the 11th Symposium on Operating System and Design Implementation
PDF, BibTex, Project, Code
Invited to Communications of the ACM
Invited to ACM Queue
Coverage: Morning Paper
OSDI '14

Peer-Reviewed Workshop Publications


Reasoning about modern datacenter infrastructures using partial histories
Xudong Sun, Lalith Suresh, Aishwarya Ganesan, Ramnatthan Alagappan, Michael Gasch, Lilia Tang, Tianyin Xu
HotOS 2021
HotOS '21
The Storage Hierarchy is Not a Hierarchy: Optimizing Caching on Modern Storage Devices with Orthus
Kan Wu, Zhihan Guo, Guanzhou Hu, Kaiwei Tu, Ramnatthan Alagappan, Rathijit Sen, Kwanghyun Park, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
NVMW 2021
NVMW '21
Too Many Knobs to Tune? Towards Faster Database Tuning by Pre-selecting Important Knobs
Konstantinos Kannelis, Ramnatthan Alagappan, Shivaram Venkataraman
15th Workshop on Hot Topics in Storage and File Systems
PDF, BibTex,
HotStorage '20
Beyond Storage APIs: Provable Semantics for Storage Stacks
Ramnatthan Alagappan, Vijay Chidambaram, Thanumalayan Sankaranarayana Pillai, Aws Albarghouthi, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
15th Workshop on Hot Topics in Operating Systems
PDF, BibTex,
HotOS '15

Peer-Reviewed Journal/Invited Publications


Can Applications Recover from fsync Failures?
Anthony Rebello, Yuvraj Patel, Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Transactions on Storage - Vol. 17, Issue 2, June 2021
PDF, BibTex
TOS '21
Strong and Efficient Consistency with Consistency-aware Durability
Aishwarya Ganesan, Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Transactions on Storage - Vol. 17, Issue 1, January 2021
Fast tracked
PDF, Bibtex,
TOS '21
Protocol-Aware Recovery for Consensus-based Storage
Ramnatthan Alagappan, Aishwarya Ganesan, Eric Lee, Aws Albarghouthi, Vijay Chidambaram, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Usenix ATC 2019
Best of the Rest
Usenix ATC '19
Protocol-Aware Recovery for Consensus-Based Distributed Storage
Ramnatthan Alagappan, Aishwarya Ganesan, Eric Lee, Aws Albarghouthi, Vijay Chidambaram, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Transactions on Storage - Vol. 14, Issue 3, October 2018
Fast tracked
PDF, BibTex,
TOS '18
Redundancy Does Not Imply Fault Tolerance
Aishwarya Ganesan, Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Transactions on Storage - Vol. 13, Issue 3, September 2017
Fast tracked
PDF, BibTex,
TOS '17
Application Crash Consistency and Performance with CCFS
Thanumalayan Sankaranarayana Pillai, Ramnatthan Alagappan, Lanyue Lu, Vijay Chidambaram, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Usenix ATC 2017
Best of the Rest
PDF, BibTex,
Usenix ATC '17
Application Crash Consistency and Performance with CCFS
Thanumalayan Sankaranarayana Pillai, Ramnatthan Alagappan, Lanyue Lu, Vijay Chidambaram, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Transactions on Storage - Vol. 13, Issue 3, September 2017
Fast tracked
PDF, BibTex,
TOS '17
Redundancy Does Not Imply Fault Tolerance
Aishwarya Ganesan, Ramnatthan Alagappan, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
USENIX ;login: Volume 42, Number 2, 2017
PDF, BibTex,
USENIX ;login: Summer '17
Hybrid NVM Enabled Datacenter Design and Optimization
Yanqi Zhou, Ramnatthan Alagappan, Amir Samam Memaripour, Anirudh Badam, David Wentzlaff
MSR-TR-2017-8 Feb 2017
PDF, BibTex,
MSR TR
Crash Consistency: Rethinking the Fundamental Abstractions of the File System
Thanumalayan Sankaranarayana Pillai, Vijay Chidambaram, Ramnatthan Alagappan, Samer Al Kiswany, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
ACM Queue July 2015
PDF, BibTex,
ACM Queue
Crash Consistency:
Thanumalayan Sankaranarayana Pillai, Vijay Chidambaram, Ramnatthan Alagappan, Samer Al Kiswany, Andrea C. Arpaci-Dusseau, Remzi H. Arpaci-Dusseau
Communications of the ACM - Vol. 58, No. 10, October 2015
PDF, BibTex,
CACM

WIPS/Posters


Atomic In-Place Updates for Non-Volatile Main Memories with KaminoTx
Amir Saman Memaripour, Anirudh Badam, Amar Phanishayee, Yanqi Zhou, Ramnatthan Alagappan, Karin Strauss, Steven Swanson

NVMW '18
Simple Crash Consistency With Streams
Thanumalayan Sankaranarayana Pillai, Ramnatthan Alagappan, Andrea Arpaci-Dusseau, Remzi Arpaci-Dusseau

FAST '16

Teaching

I enjoy teaching!

Instructor for CS 739 - Spring 2020 (co-taught by Aishwarya Ganesan).
Evaluation (as an intructor): 6.42/7.00 (ranked 2nd among graduate courses)
Nominated for the SACM CoW award (yearly teaching award given to UW CS professors)
Evaluation (course as a whole): 6.50/7.00 (ranked 1st among all courses)
I designed a graduate-level distributed systems course. This course was heavily research oriented: every class, students read 1-2 foundational papers in distributed systems on topics including fault tolerance, consensus (e.g., Paxos), distributed transactions, BFT, and distributed storage. Students also did a considerably large research project. Lecture notes, assignments, and exams are available on the course web page.

Teaching Assistant for CS 537 Introduction to Operating Systems
Responsibilities: Guest lectures, exam review lectures, designing and evaluating assignments on the xv6 research operating system.

Guest Lectures
Shivaram Venkatramans’s CS 537 (concurrency, RAID)
Mike Swift’s CS 736 (AFS)
Remzi Arpaci-Dusseau’s CS 739 - (Paxos, storage faults)

Teaching Assistant for CS 302 Introduction to Programming
Responsibilities: Designing and evaluating programming assignments in Java.

Student Mentoring

I have had the great pleasure of working with the following students!

VMware Research
Yi Xu, graduate student at UC San Diego

Undergraduate Students at UW Madison
Neil Perry, now a graduate student at Stanford University

Graduate Students at UW Madison
Yifan Dai, Yien Xu
Dax Chen, Yi-Shiun Chang, Chia-Wei Chen, Pei-Hsuan Wu
Sreya Dutta Roy, Nikita Kad, Venkat Allam, Shreeshrita Patnaik
Akshat Jain, Grishma Gupta, Venkata Malireddy
Ruohui Wang, Kaiwei Tu, Max (Mengxiao) Zhang, Emma (Yi) He
Aashish Richhariya, Akanksha, Sanchit Jain
Muthunagappan Muthuraman, Srivatsan Ramesh, Suryadev Sahadevan Rajesh, Vinith Venkatesan
Deepak Srinath, Lokit Kumar Paras, Nithin Venkatesh, Phanindra Moganti
Kumar Biplav, Aditya Rungta, Nisarg Shah, Shaurya Shekhar

Service


Program Committee HotStorage '22
Ask-Me-Anything Co-chair SOSP '21
OSDI Mentoring OSDI '21
EuroDW Mentoring EuroDW '21
Journal of Systems SEB Co-cair '21
EuroDW Program Committee EuroDW '21
Program Committee HotStorage '21 (Distinguished Reviewer)
Program Committee Systor '21
Reviewer ACM Transactions on Computer Systems '20
Program Committee HotStorage '20
Artifact Evaluation Committee Reviewer SOSP '19
Shadow Program Committee Reviewer Eurosys '19 (Best Reviewer Award)
Reviewer ACM Transactions on Storage '18
External Reviewer FAST '18
Contributor to PC reviews Eurosys '17
External Reviewer OSDI '16
External Reviewer FAST '16

Presentations and Invited Talks


Co-designing Distributed Systems and Storage Stacks @ Waterloo Oct 21 (invited)
Reliable Distributed Storage: A Local Storage Perspective @ Rutgers Aug 20 (invited)
Reliable Distributed Storage: A Local Storage Perspective @ VRG Jun 20 (postdoc interview talk)
Protocol-Aware Recovery for Consensus-Based Storage @ ATC '19 (invited conference talk)
Storage Systems at the Edge @ NSF-VMWare ECDI Summit (invited)
Fault-Tolerance, Fast and Slow: Exploiting Failure Asynchrony in Distributed Systems @ OSDI '18 (slides)
Protocol-Aware Recovery for Consensus-based Storage @ SNIA SDC '18 (invited, slides, video)
Resiliency to Storage Faults in Distributed Systems @ Google Madison May '18 (invited)
Protocol-Aware Recovery for Consensus-Based Storage @ FAST '18 (slides)
Rethinking Consensus with Local Storage in Mind @ SCI-labs 2017
Correlated Crash Vulnerabilities @ OSDI '16 (slides)
Correlated Crash Vulnerabilities @ Microsoft Gray Systems Lab

Software

PACE: To check for correlated crash vulnerabilities in distributed systems
Code on GitHub
CORDS: To test corruption tolerance in distributed systems
Code on GitHub
ALICE: To check for crash vulnerabilities in local storage systems
Code on GitHub