Sangeetha Seshadri

Learn More
Storage systems based on Phase Change Memory (PCM) devices are beginning to generate considerable attention in both industry and academic communities. But whether the technology in its current state will be a commercially and technically viable alternative to entrenched technologies such as flash-based SSDs remains undecided. To address this, it is(More)
We consider the problem of query optimization in distributed stream based systems where multiple continuous queries may be executing simultaneously. In such systems, distribution adds degrees of freedom to an already complex optimization problem. Thousands of network nodes may need to be considered for operator placements in order to support in-network(More)
We consider the problem of query optimization in distributed data stream systems where multiple continuous queries may be executing simultaneously. In order to achieve the best performance, query planning (such as join ordering) must be considered in conjunction with deployment planning (e.g., assigning operators to physical nodes with optimal ordering).(More)
—The significant IO improvements of Solid State Disks (SSD) over traditional rotational hard disks makes it an attractive approach to integrate SSDs in tiered storage systems for performance enhancement. However, to integrate SSD into multi-tiered storage system effectively, automated data migration between SSD and HDD plays a critical role. In many real(More)
Today organizations and business enterprises of all sizes need to deal with unprecedented amounts of digital information , creating challenging demands for mass storage and on-demand storage services. The current trend of clustered scale-out storage systems use symmetric active replication based clustering middleware to provide continuous availability and(More)
—This paper addresses the problem of optimizing multiple distributed stream queries that are executing simultaneously in distributed data stream systems. We argue that the static query optimization approach of " plan, then deployment " is inadequate for handling distributed queries involving multiple streams and node dynamics faced in distributed data(More)
Host-side flash caching has lately emerged as a suitable and e↵ective means of accelerating enterprise workloads. However , cache management for flash-based caching is di↵erent from traditional DRAM-based caching. A flash cache sits underneath the DRAM cache. Its position in the hierarchy combined with the unique characteristics of flash, calls for a(More)
A software defined storage environment is one in which logical storage resources and services are completely abstracted from physical storage systems. Therefore, not only can storage resources cross physical boundaries, but they can also be defined by software and provisioned automatically, for instance, by the applications that consume them. In this paper,(More)
Storage devices based on Phase Change Memory (PCM) devices are beginning to generate considerable attention in both industry and academic communities. But whether the technology in its current state will be a commercially and technically viable alternative to entrenched technologies such as flash-based SSDs still remains unanswered. To address this it is(More)