Paxos and Raft are both consensus algorithms used to ensure consistency in distributed systems. While they solve similar problems, they have different approaches and design philosophies. Characteristics Paxos Roles: Proposers, Acceptors, Learners. Phases: Two main phases (Prepare/Promise and Propose/Accept). Leader Election: Not explicitly defined, often implemented using Multi-Paxos to handle multiple proposals efficiently. Use Cases:…
The Paxos consensus algorithm is a fundamental concept in distributed computing that ensures a group of distributed systems can agree on a single value, even in the presence of failures. Developed by Leslie Lamport, Paxos is widely used in systems where consistency and fault tolerance are critical, such as databases and distributed ledgers. Consensus Problem…
The Raft consensus protocol is a distributed consensus algorithm designed to be more understandable than other consensus algorithms like Paxos. It ensures that a cluster of servers can agree on the state of a system even in the presence of failures. Key Concepts Raft divides the consensus problem into three relatively independent subproblems: Leader Election:…
Distributed systems are becoming increasingly important in various applications, such as cloud computing, , and peer-to-peer networks. One of the challenges in designing robust distributed systems is dealing with Byzantine faults, a type of fault that can be particularly difficult to detect and handle. Byzantine faults, named after the Byzantine Generals’ Problem, involve components of…
Being sync or async for data writing of a file system or a network file system affects the data integrity. Is Samba sync or async for writes? In summary, Samba writes are async by default. But the behavior is configurable. Here is a great summary by Eric Roseme. Samba defaults to asynchronous writes. smbd writes…
In memory hierarchical, it needs to be coherence and consistency. However, they are different things. What are the differences? Memory coherence: a memory system is coherent if any read of a data item returns the most recently written value of that data item (what values can be returned by a read). Memory consistency: A memory…
When we design a system, we may want our systems to be consistency, scalability and so on. Currently, there are some famous consistency algorithms. How to understand them easily. 1, Paxos and its extensions 2, Replicated State Machine mechanisms 3, Quorum Welcome to adding other famous consistency algorithms and its understanding ;-) Reading text books…
Some important concepts in distributed system like Hadoop distributed file system, Google file system and so on. Answer from http://www.quora.com/Whats-the-difference-between-Reliability-Durability-and-Availability-for-data-storage-system The difference between durability and availability is fairly simple. Durability is about what happens when all power goes out everywhere. Has all data been written to stable storage that doesn’t require power (e.g. disk/flash), in…
Technical discussions on Redis. Redis internal documentation: http://redis.io/topics/internals Redis manifesto, the philosophy behind Redis: http://oldblog.antirez.com/post/redis-manifesto.html Redis Architecture: Overview Of Redis Architecture Redis data model and eventual consistency: http://antirez.com/news/36
Which are the consistency models used for distributed systems? Papers that survey the consistency models Robert C. Steinke and Gary J. Nutt. 2004. A unified theory of shared memory consistency. J. ACM 51, 5 (September 2004), 800-849. DOI=10.1145/1017460.1017464 http://doi.acm.org/10.1145/1017460.1017464 David Mosberger. 1993. Memory consistency models. SIGOPS Oper. Syst. Rev. 27, 1 (January 1993), 18-26. DOI=10.1145/160551.160553…
The word “viral” has received a lot of attention over the last few years and is applied to different types of content to describe how quickly it has spread and gained popularity. Many times, you’ll hear people speak about their idea and how fast it will spread while assuming that it will “go viral”, but…
The public cloud storage services like Amazon S3, Google Cloud Storage and Windows Azure Storage replicate the data to ensure high availability. On the other hand, with data being replicated, the storage services exhibits certain data consistency models. Different cloud service providers employ different data consistency models nowadays. In this post, we survey the data…
Understanding the literature is usually the first step to do research, which is the same for systems research on cloud computing. A reading list may help a lot to those that just start in cloud computing research. Prof. Lin Gu, my PhD supervisor, compiled a reading list for system research on cloud computing. The reading…