MANJUNATH RAJASHEKHAR
163 Chattanooga St
San Francisco, CA 94114
cell: (650) 521-1544
manj@cs.stanford.edu
http://www-cs-students.stanford.edu/~manj
EDUCATION
Masters of Science in Computer Science
Stanford University, California
Sep '05 – Jun '07
Specialization: Systems
WORK EXPERIENCE
Staff Engineer
Cache Team
Twitter
Sept '10 – present
Designed, architected and built the caching system at Twitter, scaling it from 50 million to more
than 200 million users. As a part of this group, I built and open-sourced Twemcache (Twitter
memcached) and Twemproxy (memcached & redis proxy). Twemcache and Twemproxy are the
fundamental building blocks of the Twitter's caching system and have been instrumental in scaling
the backend systems at Twitter and improving the performance of Twitter’s core infrastructure
components.
I also worked closely with the kernel team to tune the Linux kernel in Twitter’s datacenter that
enabled us to run low latency and high throughput network services. As a part of the performance
tuning effort of the caching system, I built and open-sourced Twemperf – a tool for measuring and
analyzing memcached server performance.
I also built and open-sourced Fatcache - a memcache on SSD that serves as a cache for your big
data. Fatcache enables us to use SSD technology to bridge the caching divide between volatile
RAM and non-volatile databases and file systems when many gigabytes of data needed to be
cached on a single machine.
Member of Technical Staff
Virtual Machine File System (VMFS) group
VMware
Aug '07 – Sept ‘10
VMFS is a high performance cluster file system over block storage that enables storage
virtualization optimized for virtual machines. As a part of this group, here are some of my
contributions:
Lock Manager for VMFS-5: Designed and developed the lock manager for the next generation of
cluster file system called VMFS-5: the successor of VMFS-3. Unlike VMFS-3, the VMFS-5 lock
manager scales linearly with the number of nodes in the cluster and hence enables VMFS-5 to
scale gracefully when subjected to limits of increased VM density and node connectivity in an
enterprise cloud.
For an 8-node cluster setup, the new lock manger exhibited ~40% improvement over its
predecessor during concurrent updates of shared resources in the cluster.
Garbage Collector: Designed and implemented an incremental, online garbage collector to
reclaim leaked heartbeat and journal blocks on an active VMFS.
Investigated and implemented algorithmic optimization for Read-Only and Multi-Writer on-disk
locks in VMFS.
Software Development Engineer (Summer Intern)
Core File Systems (CFS) group
Microsoft
Jul '06 – Sept '06
I worked in the Distributed File System Replication (DFSR) team, where I developed a lease-based
file locking prototype for the DFSR service.
I also contributed towards Longhorn Server Beta 3 release by designing and implementing
performance counters for the DFSR service using PerfLibV2 library.
Software Engineer
Citrix Systems (previously NetScaler)
Jul '03 - Aug '05
Worked in the kernel group of SSLVPN team as a FreeBSD kernel programmer
Intranet IP: Designed and implemented the Intranet IP feature to manage the assignment of
unique routable IP address in the intranet domain for the SSLVPN feature.
2
Single Sign-On (SSO): Designed and implemented the 401 pop-up based Single Sign-On (SSO)
mechanism and integrated it with the existing SSLVPN feature.
Designed and implemented the forward proxy cache redirection feature.
Policy Engine Enhancement Framework: Implemented enhancements to policy engine
framework, that provided support for compound expressions, run time modification of expressions
and priority based evaluation.
Project Trainee
Center for Artificial Intelligence and Robotics (CAIR)
Defense Research and Development Organization, India
Feb '03 - May '03
TLS Library: Designed and implemented TLS protocol (rfc2246) compliant library, which provided
network application programmer with a convenient set of interfaces to implement a secure
application compliant with TLS protocol.
RESEARCH AND TEACHING EXPERIENCE
Research Assistant (Guibas Group)
Jan '06 – Jun '07
Research on Sensor Networks under Professor Leonidas Guibas.
Teaching Assistant for the “Low-Power Wireless Networking” (cs244e) class at Stanford. Duties
involved teaching and evaluating lab assignments, holding office hours to clarify students’
questions, and giving guest lectures.
PUBLICATIONS
Ajay Mani, Manjunath B. Rajashekhar, and Philip Levis, “TINX: A Tiny Index Design for Flash
Memory on Wireless Sensor Devices.” In Proceedings of the Fourth ACM Conference on
Embedded Networked Sensor Systems (Sensys 2006), Poster Session, Pages: 425 – 426.
SELECTED GRADUATE PROJECTS
Pintos: Designed and Implemented multithreading, multiprogramming, virtual memory and file
system on top of Pintos operating system.
Data Mining Project: Frequent Itemsets Mining in Distributed Wireless Sensor Networks
SELECTED UNDERGRADUATE PROJECTS
Peer-to-peer network: Designed and implemented File sharing application (Napster like model)
over P2P network on Linux using a “centralized server with content lookup”.
User-level Network Address Translator (NAT): Designed and Implemented a Dynamic
Network Address Translator called IP masquerading in the user space using packet socket and
Libnet library.
COMPUTING SKILLS
Platforms: Linux, FreeBSD, Windows.
Languages: C, C++, Java, Python.
Programming: Kernel programming (FreeBSD), Unix system programming (IPC, Socket), Unix
shells (bash, tcsh), Flex, Yacc.
Software: MS Office, GTK+, apache modules, perforce (P4), VIM, VMWare.
MISC
- BASES e-challenge 2007 quarter finalist.
- Former member of Ballet Folklorico de Stanford.