Distributed File Sytsem :: Essays Papers

Distributed File SytsemIntro stopping point is an observational distributed appoint remains being developed at Carnegie Mellon University. Dr. M. Satyanarayanan heads this group whose invention is to design and implement a distributed bear down system that allows for transparent unstable computing in a client server environment. The goals set aside for CODA include disconnected operation for mobile clients, failure resistance, performance, scalability and security. architectureMost of the aspects of CODAs basic architecture are contagious from its predecessor AFS (Andrew File System). Like AFS, CODA makes a distinction in the midst of servers and clients. The CODA workstation servers consist of blow upitions available to the file server. The partitions are made up of volumes that contain files. The volumes are set up like a directory structure, a root directory and the tree below it. A typical server would break hundreds of volumes of around 10MB each. The use of volumes helps to make large amounts of entropy more compliant and flexible. CODA stores volume and directory information along with access control lists and file attributes in raw partitions. These partitions are accessed through a log base recoverable virtual memory package (RVM). Only the file data is stored in the server partition files. individually of the volumes has a name and an ID. Volumes evict be mounted anywhere in /coda except for on a lower floor existing directories. A new directory will be created as part of the mount process (the volume name cannot conflict with existing directories in order to eliminate confusion). CODA makes the mounting points invisible to the user they seem as regular directories.Files in CODA are identified by a FID (File identifier). The Fid consists of three 32 bit integers the VolumeId, a VnodeId and an Uniquifier. The VolumeId identifies the volume the file resides in, the VnodeId is the inode number of the file and the Uniqui fier guarantees no FID is ever used more than once. CODA stores replicated copies of volumes on a group of servers for higher availability and reliability. The list of the servers that crap a copy of the replicated volume is the VSG or Volume Storage Group. Each replicated volumes VolumeId is also replicated. The replicated VolumeIds keep the VSG and the local volumes of each particle together.Connected OperationThe inner workings of a file system operation in CODA begin in much the alike(p) way they would in many other file systems.