IOSR Journal of Computer Engineering (IOSR-JCE) e-ISSN: 2278-0661,p-ISSN: 2278-8727, Volume 17, Issue 1, Ver. IV (Jan – Feb. 2015), PP 60-64 www.iosrjournals.org DOI: 10.9790/0661-17146064 ww.iosrjournals.org 60 | Page Cloud Storage: Focusing On Back End Storage Architecture Sarishma, Kartik Mishra CSEwithspecialization inCloud Computing and Virtualization Technology (2012-2016) UniversityofPetroleum&EnergyStudies, Dehradun,India Abstract: In the modern era of mobile and cloud computing, people are becoming more and more dependent on digital devices. In order to execute any application, a certain amount of storage space is mandatory which is to be used by the application as its own warehouse to store its data.While designing any storage architecture, we have data as the centre of attraction around which whole of our application design revolves.Cloud storage is a hot topic nowadays as the data storage capacity rates are increasing manifold’s every year and has thus become a reality that all data centers and organizations should consider. This huge amount of data, thus poses a challenge for the construction of a good well defined, fault prone back end storage.This paper representsthe different available architectures that are used in storage technology foundation. Beginning with a conceptual overview of the SNIA reference model for cloud storage,the key concepts of cloud and other technologies which form a base for cloud storage are discussed. Followed by this, the three standard architectures related to cloud storage are discussed which are basicallyStorage Area Network (SAN), Direct Attached Storage (DAS) and Network Attached Storage(NAS). The paper concludes by pinpointing the future research and open challenges related to cloud storage. Keywords: Mobile Computing, Storage architecture, Cloud Storage, SNIA. I. Introduction Since a decade ago, the wide demand of increase in storage capabilities of devices aroused the need of well-formed storage architectures to meet the voracious storage demands. Earlier users used to buy their own hardware to store and carry their personal data. Slowly but unceasingly the amount of data which different users produced increased and so did the demand of storage mediums. Data can be considered as a pool of raw facts and figures which can be combined together to create a logical meaning. Depending upon the storage and managing medium of data, it can be classified into two categories, structured data and unstructured data. As the name suggest, structured data is stored in the form structures i.e. rows and columns which makes it much easier for retrieval as well as for access. On the other hand, unstructured data is the one which cannot be stored in the form of structures i.e. rows and columns and therefore, retrieval and access to unstructured data becomes pretty much difficult. Statistically speaking, about 80% of the data stored on cloud is unstructured which makes it difficult to use. With the advent of cloud computing, users are facilitated with the view of unlimited storage space being available to them on pay per use basis. Individual users generate more data in the form of digital content such as audio, video, images, mp3, documents etc. as compared to the data generated by business enterprises. People leverage the availability of storage mediums to such an extent that they can move anywhere around the world with their own personal huge amount of data. They can communicate with people across the globe and share data with the geographically apart areas. This communication and sharing when viewed from an external perspective is quite simple but coming to the technicalities it becomes pretty hard to handle such a large amount of stored content. When it comes to transfer and sharing of data while deploying cloud services, it becomes important to manage every process efficiently. The segregation among data, security checks, latency, cost etc. are the factors which influence the cloud services related to storage. Uploading this data on cloud servers is done via network and it therefore becomes very important to focus on what kind of storage architecture a particular cloud service provider is using. There are a large number of available architectures for cloud storage but we are presenting the most viable, suitable and accepted architectures which are SAN, NAS and DAS. SAN is acronym for Storage Attached Network that provides access to consolidated, block level data storage. NAS stands for Network Attached Storage and is a file-level computer data storage server connected to a computer network providing data access to a heterogeneous group of clients. DAS is a directly attached storage in the form of hard disk drives connected through a Host Bus Adapter (HBA). Rest of the paper is organized as: Section 2 explains the fundamentals or background related to cloud assisted storage mechanisms. Section 3 explains the SNIA reference model for cloud storage accompanied with a well-definedself-explanatoryreference diagram. Section 4 presents the selected architectures which lay the foundation of cloud storage which are followed bythree types of architectures i.e. SAN, NAS and DAS. The future research and open challenges related to cloud storage are presented in the section 5. The last section i.e. section 6 concludes our paper.