Semester Project

Projects

The following projects are given to CS graduate students.

Project 1: Erasure Code in Hadoop

• Implement an erasure code into Hadoop system
• Hadoop Version: 2.7 or higher
• Erasure Code: you can select one, but not RS (We recommend facebook LRC code)
• Test the storage efficiency of your proposed code
• Report and Source Code are required
• Source Code should be checked by TA
• References:
• Jerasure: http://web.eecs.utk.edu/~plank/plank/www/software.html
• HDFS-Xorbas: http://smahesh.com/HadoopUSC/

Project 2: Distributed Lock Design

• Design a simple consensus system, which satisfy the following requirements
• Contain one leader server and multiple follower server
• Each follower server has a replicated map, the map is consisted with the leader server
• The key of map is the name of distributed lock, and the value is the Client ID who owns the distributed lock



• Support multiple clients to preempt/release a distributed lock, and check the owner of a distributed lock
• For preempting a distributed lock
• -- If the lock doesn't exist, preempt success
• -- Otherwise, preempt fail
• For releasing a distributed lock
• -- If the client owns the lock, release success
• -- Otherwise, release fail
• For checking a distributed lock
• -- Any client can check the owner of a distributed lock
• To ensure the data consistency of the system, the follower servers send all preempt/release requests to the leader server
• To check the owner of a distributed lock, the follower server accesses its map directly and sends the results to the clients
• When the leader server handling preempt/release requests
• If needed, modify its map and sends a request propose to all follower servers
• When a follower server receives a request propose
• -- modify its local map
• -- check the request is pending or not
• -- if the request is pending, send an answer to the client
• In this system, all clients provide preempt/release/check distributed lock interface
• When a client is initialized
• Define the IP address of the target server
• Generate the Client ID information based on the user information(UUID)
• References
• Data structure of a client in the consensus system

Project 3: Distributed File System Design

• Design a Mini Distributed File System (Mini-DFS), which contains
• A client
• A name server
• Four data servers



• Mini-DFS is running through a process. In this process, the name server and data servers are different threads
• Basic functions of Mini-DFS
• Read/write a file
• Upload a file: upload success and return the ID of the file
• Read the location of a file based on the file ID and the offset
• File striping
• Slicing a file into several chunks
• Each chunk is 2MB
• Uniform distribution of these chunks among four data servers
• Replication
• Each chunk has three replications
• Replicas are distributed in different data servers
• Name Server
• List the relationships between file and chunks
• List the relationships between replicas and data servers
• Data server management
• Data Server
• Read/Write a local chunk
• Write a chunk via a local directory path
• Client
• Provide read/write interfaces of a file
• Mini-DFS can show
• Read a file (more than 7MB)
• Via input the file and directory
• Write a file (more than 3MB)
• Each data server should contain appropriate number of chunks
• Using MD5 checksum for a chunk in different data servers, the results should be the same
• Check a file in (or not in) Mini-DFS via inputting a given directory
• By inputting a file and a random offset, output the content
• Bonus points
• Add directory management
• Write a file in a given directory
• Access a file via "directory + file name"
• Recovery
• Delete a data server (three data servers survive)
• Recover the data in the lost data server
• Redistribute the data and ensure each chunk has three replicas

Project 4: Metadata Management in DFS

• Design a simple metadata management module for a distributed file system. Establish a distributed metadata cluster and a POSIX API based client
• The metadata management has the following functions
• Basic command set: support metadata operations via POSIX-based API
• i.e., mkdir, create file, readdir, rm file, stat, etc
• file handle can be ignored
• Distribution of metadata
• Metadata are distributed among various metadata servers
• Tests on the metadata management functions
• Input: Input the specified files & directories by client
• Output
• Traverse the files via readdir command
• List the status of a file via stat command
• Etc
• Write the metadata of these file operations into the metadata server
• Give the data distribution information of the whole cluster
• Consistent with other metadata servers
• Additional scores
• Support metadata server failover (process level)
• Support metadata server failure
• No metadata lost in the failure
• Implementation on the read/write operations of a file

Project Management

You should strongly consider using either Subversion or CVS to perform source code control for your project and the paper you write describing it. I suggest Subversion.

I also strongly suggest writing your course project report using LaTeX. It is the de-facto tool in which most CS research papers are written. While it has a bit of start up cost, it's much easier to collaboratively write complex research papers using LaTeX than using word.

Writing Papers

• Collected resources about writing and research

Analysis

• Books: Raj Jain, the Art of Computer Systems Performance Analysis - a very good overview of lots of mathetmatical techniques and queueing bits, aimed at a systems audience