Networked Shared Storage

Peer-to-peer storage systems organize a collection of symmetric nodes to store data without the use of centralized data structures or operations. As a result, they can scale to many thousands of nodes and can be formed directly by clients. This paper describes the design and implementation Mammoth, which implements a traditional UNIX-like hierarchical file system in a peer-to-peer fashion. Each Mammoth node stores a potentially arbitrary collection of directories and files that may be replicated on multiple nodes. The only thing that links these nodes together is that each metadata object encodes the network addresses of the nodes that store it. Data is replicated by a background process whose operation is simplified by the fact that files are stored as journals of immutable versions. An optimistic replication technique is used to allow nodes to read and write whatever version of data they can access, while also ensuring consistency when nodes are connected. In the event of temporary failure, eventual consistency is achieved by ensuring that every replica of a directory or file metadata object receives all updates to the object, irrespective of delivery order. While an update is being propagated every node that receives it cooperates to ensure that the update is delivered, even if the original sender fails. Our prototype is implemented as a user-level NFS server. Its performance is comparable to a standard NFS server and it will be publicly available soon.

1985

This paper presents the design and rationale of a distributed file system for a network of more than 5000 personal computer workstations. While scale has been the dominant design influence, careful attention has also been paid to the goals of location transparency, user mobility and compatibility with existing operating system interfaces. Security is an important design consideration, and the mechanisms for it do not assume that the workstations or the network are secure. Caching of entire files at workstations is a key element in this design. A prototype of this system has been built and is in use by a user community of about 400 individuals. A refined implementation that will scale more gracefully and provide better performance is close to completion.

Proc. Int. Web Caching Workshop, 1999

This paper comtemplates two important information-provisioning pradigms-caching and replication, and proposes a new approach on network storage system in order to meet the increasing demands for large les. The key idea of our system is to have two tailor-made servers for large and small object, respectively. Modi ed proxy cache is responsible for store and deliver small objects. For large objects, we introduce a replication mechanism. By replicating large objects in a dedicated server and relaying through a proxy cache, storage can be fully utilized. Large objects can be accessed without a priori knowledge of server location. Our system provides a scalable solution to the continuing growth of tra c volume while it retains transparency for users. It is also designed to ensure compatibility with existing networking standards, applications and system software.

ACM Computing Surveys, 1990

The purpose of a distributed file system (DFS) is to allow users of physically distributed computers to share data and storage resources by using a common file system. A typical configuration for a DFS is a collection of workstations and mainframes connected by a local area network (LAN). A DFS is implemented as part of the operating system of each of the connected computers. This paper establishes a viewpoint that emphasizes the dispersed structure and decentralization of both data and control in the design of such systems. It defines the concepts of transparency, fault tolerance, and scalability and discusses them in the context of DFSs. The paper claims that the principle of distributed operation is fundamental for a fault tolerant and scalable DFS design. It also presents alternatives for the semantics of sharing and methods for providing access to remote files. A survey of contemporary UNIX@-based systems, namely, UNIX United, Locus, Sprite, Sun's Network File System, and ITC's Andrew, illustrates the concepts and demonstrates various implementations and design alternatives. Based on the assessment of these systems, the paper makes the point that a departure from the approach of extending centralized file systems over a communication network is necessary to accomplish sound distributed file system design.

… " of Bucharest Scientific Bulletin, Series C: …, 2010

Reţelele peer-to-peer sunt sisteme distribuite ideale pentru a stoca date replicate, în scopul de a le putea obţine rapid şi transparent, orideunde am dori. O problemă importantă, când vine vorba de aceste sisteme distribuite, este replicarea datelor critice într-o manieră persistentă. Această problemă o adresăm prin lucrarea de faţă, propunând un mecanism suplimentar de asigurare a redundanţei, în plus faţă de mecanismul natural al DHT-ului Chord, de replicare pe un număr fix de succesori. Deşi am prevăzut pentru cercetarea viitoare rularea unor teste intensive de stres pentru prototipul curent, chiar şi rezultatele obţinute până în prezent par să confirme capabilităţile de a adapta gradul de redundanţă datelor critice atunci când e necesar sau la cerere.

2000

In a distributed file system built on network attached storage, client computers access data directly from shared storage, rather than submitting I/O requests through a server. Without a server marshaling access to data, if a computer fails or becomes isolated in a network partition while holding locks on cached data objects, those objects become inaccessible to other computers until a locking authority can guarantee that the lock holder will not again directly access these data. We describe a server that acts as the locking authority and implements a lease-based protocol for revoking access to data objects locked by an isolated or failed computer. When a lease expires, the server can be assured that the client no longer acts on locked data, and can safely redistribute locks to other clients. During normal operation, this protocol invokes no message overhead, and uses no memory and performs no computation at the locking authority.

1994

Performance suffers under NFS Version 2 because the protocol requires servers to write data and file system metadata to stable storage (usually disk) synchronously, before replying successfully to a client WRITE request [Ousterhout90] . The performance problem with synchronous writes was recognized early. NFS Version 2 has an artifact of a proposed interface for asynchronous writes (the undefined WRITECACHE procedure).

Distributed Operating Systems, 2010

The classic network file systems we examined, NFS, CIFS, AFS, Coda, were designed as client-server applications. Clients talk to a service that, in this case, happens to be a file service. The actual file service is offered by a single machine. Where multiple machines are used, the administrator is responsible for diving up file resources (e.g., home directories) among individual servers and the the entire resource (e.g., your home directory) is fully served from a single server. In Coda, which supports replication, it is up to the administrator to define the set of machines that hold volume replicas. This is not the kind of approach that we want to use if we want to divide our files among thousands or tens of thousands of machines. For an example of handling this environment, we will look at two closely-related file systems: the Google File System (GFS) and the Hadoop Distributed File System (HDFS). The latter is an open source version (and minor variant) of the former.

IEEE Transactions on Parallel and Distributed Systems, 2019

We present NICE, a key-value storage system design that leverages new software-defined network capabilities to build clusterbased network-efficient storage system. NICE presents novel techniques to co-design network routing and multicast with storage replication, consistency, and load balancing to achieve higher efficiency, performance, and scalability. We implement the NICEKV prototype. NICEKV follows the NICE approach in designing four essential network-centric storage mechanisms: request routing, replication, consistency, and load balancing. Our evaluation shows that the proposed approach brings significant performance gains compared with the current systems design: up to 7× put/get performance improvement, up to 2× reduction in network load, 3× to 9× load reduction on the storage nodes, and the elimination of scalability bottlenecks present in current designs.

ACM SIGOPS Operating Systems Review, 1985

This paper presents the design and rationale of a distributed file system for a network of more than 5000 personal computer workstations. While scale has been the dominant design influence, careful attention has also been paid to the goals of location transparency, user mobility and compatibility with existing operating system interfaces. Security is an important design consideration, and the mechanisms for it do not assume that the workstations or the network are secure. Caching of entire files at workstations is a key element in this design. A prototype of this system has been built and is in use by a user community of about 400 individuals. A refined implementation that will scale more gracefully and provide better performance is close to completion.