Object-based Storage

This literature survey is the only work so far where the overall progress in object based storage technology has been analyzed, following its standardization. It also illustrates how the trends of recent research fit into the broad scope of the object based storage environment, thus bringing out the current status of the technology, while simultaneously providing a reality check for the concept. A special feature of this survey is an attempted comparison of existing object based file systems, mainly from a design perspective. Abstract Object-based storage is a new technology which provides intelligence at the storage device. The object storage device (OSD) interface has recently been standardized. The main characteristic of an OSD is " intelligent data layout ". Its advantages include scalability, security, reliability, performance and ease of management. This literature survey looks at the capabilities of object-based storage, and explores how it improves data sharing, security, and device intelligence. It analyzes various aspects of object based storage such as file system design, application based optimizations and so on, in order to understand the advantages of this upcoming storage technology. Many of the ideas presented in this survey suggest extensions to the OSD interface to enhance performance, security, quality of service and so on. Hence the interface is still evolving. 1. Introduction The evolution and stability of current storage interfaces (SCSI and ATA/IDE) has allowed continual advances in both storage devices and applications, without frequent changes to the standards. However, since the interface ultimately determines the functionality supported by the devices, current interfaces are holding system designers back. Storage technology has progressed to the point that a change in the device interface is needed. Object-based storage [1] is an emerging technology designed to address this problem. The OSD (object storage device) interface has recently been standardized (as the ANSI T10 Object-based Storage Devices Standard). The main characteristic of an OSD is " intelligent data layout ". A storage object is a logical collection of bytes on a storage device, with well-known methods for access, attributes describing characteristics of the data, and security policies that prevent unauthorized access. Unlike blocks, objects are of variable size and can be used to store entire data structures, such as files, database tables, medical images, or multimedia. Objects can be regarded as the convergence of two technologies: files and blocks. Files provide user applications with a higher-level storage abstraction that enables secure data sharing …