Ivan Voras

An early comparison of commercial and open-source cloud platforms for scientific environments

Cloud computing promises efficient use of hardware resources through virtualization and elastic computing facilities. Various cloud computing solutions have emerged on the market from open-source communities and commercial vendors. In this paper we discuss criteria for feature comparison of private cloud platforms and compare several open-source and commercial products. We test performance of hypervisors used in these clouds with a set of benchmark suites containing tests for various aspects of the system. We discuss the results in the context of what is commonly described as a scientific workload. The described feature and performance differences can help make wiser platform choices.

Network distributed file system in user space

File systems have traditionally been implemented in the operating systems kernel to ensure maximum possible speed and integration with the rest of the operating system, and this was true even for network file systems such as NFS. However, available CPU power on mainstream architectures continues to increase daily at a rate which is not closely followed by speed of computer network equipment. When considering development of network-distributed file systems today it becomes clear that speed improvements offered by pure kernel-side implementations are no longer significant given the bandwidth and latencies of computer networks. Recent efforts in enabling user-space file system implementations on free/open source Unix-like operating systems have made it possible to create a solution for distributing file system data over computer networks entirely in user-space. In this work we present such a solution

A high performance memory database for web application caches

the trivially distributed file system

Web-enabling cache daemon for complex data

This paper presents the architecture and characteristics of a memory database intended to be used as a cache engine for web applications. Primary goals of this database are speed and efficiency while running on SMP systems with several CPU cores (four and more). A secondary goal is the support for simple metadata structures associated with cached data that can aid in efficient use of the cache. Due to these goals, some data structures and algorithms normally associated with this field of computing needed to be adapted to the new environment.

Characteristics of multithreading models for high-performance IO driven network applications

One of the most common basic techniques for improving the performance of web applications is caching frequently accessed data in fast data stores, colloquially known as cache daemons. In this paper we present a cache daemon suitable for storing complex data while maintaining fine-grained control over data storage, retrieval and expiry. Data manipulation in this cache daemon is performed via standard SQL statements so we call it SQLcached. It is a practical, usable solution already implemented in several large Web sites.

A hierarchical file system interface to datyabase-based content management application

In a technological landscape that is quickly moving toward dense multi-CPU and multi-core computer systems, where using multithreading is an increasingly popular application design decision, it is important to choose a proper model for distributing tasks across multiple threads that will result in the best efficiency for the application and the system as a whole. The work described in this paper creates, implements and evaluates various models of distributing tasks to CPU threads and investigates their characteristics for use in modern high-performance network servers. The results presented here comprise a roadmap of models for building multithreaded server applications for modern server hardware and Unix-like operating systems.

Adapting the Bloom filter to multithreaded environments

When considering the usability of computer applications one, of the most important factors is the interface they provide for data manipulation. Historically, though each application has defined its own user interface, some types of interfaces have emerged as most applicable for certain types of data. Over time, some applications (or types of applications) have gained enough popularity that they became ubiquitous and well-known to most computer users to the extent that users consider them the norm, and as such, optimal for their daily tasks. In this paper we present an idea and implemented method of exposing data from a Web content management system in the form of hierarchical file system, manageable and editable by usual file management and office application tools

Something old is new again: reimagining the oldest social networking platform

Many classical algorithms like the Bloom filter were envisioned and created at a time when computers were the size of rooms and multithreading was not yet even explored theoretically. The landscape of modern mainstream computer systems today is heavily dominated with multi-core CPU-s but the effort to make full use of such systems is still ongoing. The Bloom filter has proven itself useful both as a core algorithm and as a supportive or optimizing addition to other data classification algorithms. This work explores adaptations to the basic Bloom filter algorithm for use in multithreaded applications on contemporary SMP systems and the consequences of such adaptations to its overall efficiency.

Disturbing web-based content management system - FERweb

The phenomenon of social networking has entered the lives of millions of people via the ubiquitous Web-based platforms such as Facebook and Google+ which are centralized platforms completely controlled by single entities. However, a complete parallel message-passing infrastructure already exists and has the benefit of 30 years experience and investments: the SMTP e-mail network, which together with the latest technologies can be utilized to provide a completely decentralized, convenient, private and even fault-tolerant social networking platform. This work in progress aims to design and implement a proof of concept of such idea.

Evaluating open-source cloud computing solutions

. This work explores various ways of distributing the FERweb CMS system (a webbased Content Management System of the University of Zagreb, Faculty of Electrical engineering and computing) Primary aim of this project is enhancing the performance of the system, within the constraint that the efforts must be based on existing technologies used in the project and with minimal impact on the existing code.