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Data protection using backup is one of the most critical IT management operations to ensure business continuity, which is also constantly evolving due to the emerging challenges in the “Big Data Era.” In this paper, we introduce our ongoing research effort in designing intelligent enterprise backup management solutions by obtaining actionable insights from voluminous backup job metadata across data...
Expansion of IT applications creates serious needs for environments with huge storage. In storage systems, capacity and agility are two factors which face limitations. This article evaluates the role of different techniques with regard to the possible methods for accessing to the storage systems. We have prepared three different scenarios using direct, semi-virtual, and virtual attachment models....
For traditional data warehouses, mostly large and expensive server and storage systems are used. In particular, for small- and medium size companies, it is often too expensive to run or rent such systems. These companies might need analytical services only from time to time, for example at the end of a billing period. A solution to overcome these problems is to use Cloud Computing. In this paper,...
Multi-core processor architectures can have significant performance advantage over traditional single core designs, which are limited by power and processor complexity. Predictions based on Moore's Law state that a processor chip may accommodate thousands of cores in 5-10 years. Can software scale with the number of cores and achieve the performance potential? This paper uses two OLTP (online transaction...
Resurgence of virtualization calls for suitable benchmark to validate the design of virtualization system. Among the virtual machines' performance, I/O especially disk I/O is the most critical one. Since I/O is a key factor that impacts virtual machine performance, this paper introduces a benchmark-vBench for disk I/O micro-performance evaluation of virtual machine. vBench is mainly consisted of serial...
We propose a new extension for index based scheduling rules which adds a global system perspective by estimating how much a job could benefit from an immediate processing. We implement this criterion in the ATC rule and compare the performances of the standard ATC and the extended rule ATCG. It is shown that ATCG performs better than ATC, especially when system loads are high and processing times...
The paper focuses on implementation of association pattern between the network performances and the general network faults. We use network simulation tool, OPNET, to accomplish network simulations of different network faults and different situations based on VoIP. Network performance parameters such as end-to-end delay, jitter, traffic dropped, queuing delay, link throughout, link utilization are...
Complex event processing (CEP) is a branch of stream data mining, which is usually used to discover event patterns. Generally, a complex event processing engine uses nonprocedural declaration language and state machine to define event patterns. It generates synopses of universe data by sliding window model, therefore could identify event patterns which users care about from rapidly changing and potentially...
We propose and evaluate a novel improvement to a previously published, unreliable covert channel based on the network traffic of multiplayer, first person shooter online games (FPSCC). Covert channels typically embed themselves within pre-existing (overt) data transmissions in order to carry hidden messages. FPSCC encodes covert bits as slight, yet continuous, variations of a player's character's...
We consider new queueing model describing the operation of cyclic polling systems in very hight throughput wireless mesh-networks. Queues are cyclically polled by two servers. Some of queues are served by both servers, the rest are served just by one of them. To investigate the model, we apply the mean value analysis to derive the mean waiting times in queues and provide the numerical examples.
This paper describes a software framework we designed and implemented for the development and research in the area of multimodal human-computer interface. The proposed framework is based on publish/subscribe architecture, which allows developers and researchers to conveniently configure, test and expand their system in a modular and incremental manner. In order to achieve reliable and efficient data...
Resilience against unexpected server failures is a key desirable function of quality-assured service systems. A good capacity planning decision should cost-effectively allocate spare capacity for exploiting failure resilience mechanisms. In this paper, we propose an optimal capacity planning algorithm for server-cluster based service systems,particularly the ones that provision composite services...
Disk time slicing is a promising technique for storage performance insulation. To work with cluster based storage, however, time slices associated with striped data must be co-scheduled on the corresponding servers. This paper describes algorithms for determining global time slice schedules and mechanisms for coordinating the independent server activities. Experiments with a prototype show that, combined,...
Most Byzantine fault-tolerant state machine replication (BFT) algorithms have a primary replica that is in charge of ordering the clients requests. Recently it was shown that this dependence allows a faulty primary to degrade the performance of the system to a small fraction of what the environment allows. In this paper we present Spinning, a novel BFT algorithm that mitigates such performance attacks...
Database clusters based on share-nothing replication techniques are currently widely accepted as a practical solution to scalability and availability of the data tier. A key issue when planning such systems is the ability to meet service level agreements when load spikes occur or cluster nodes fail. This translates into the ability to provision and deploy additional nodes. Many current research efforts...
We present a collection of techniques for exploiting latent I/O asynchrony which can substantially improve performance in data-intensive parallel applications. Latent asynchrony refers to an application's tolerance for decoupling ancillary operations from its core computation, and is a property of HPC codes not fully explored by current HPC I/O systems. Decoupling operations such as buffering and...
Session Initiation Protocol (SIP) is adopted as the main signaling protocol for the IP Multimedia Subsystem (IMS). Large deployment of SIP servers in Next Generation Networks (NGN) requires studying the behavior and performance of SIP servers under both normal and overload conditions, which may happen in such networks with a vast number of users. In this paper a measurement-based study is performed...
In a mobile database environment, multiple mobile hosts may access the similar data items independent of their physical locations. This may result in inconsistency of data items. Several Concurrency control techniques have been proposed to eliminate the inconsistency of data items. However because of the mobility and disconnections, the traditional concurrency control strategies are not suitable in...
The continual advancement and capacity of RFID technology is spurring a wide acceptance and growing interest in various entities in the supply chain. Its benefits, as opposed to the prevalent bar code, are enticing with myriad possibilities envisioned to attaining better operational efficiencies. In an era where product lifecycles and order lead times are ever decreasing and customer demands tenacious,...
Although server technology provides a means to support a wide range of online services and applications, their ad-hoc configuration poses significant challenges to the performance, availability and economical costs of applications. In this paper, we examine the impact of server configuration on the central tradeoff between service performance and availability. First, we present a server model as a...
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