Systems can become misconfigured for a variety of reasons such as operator errors or buggy patches. When a misconfiguration is discovered, usually the first order of business is to restore availability, often by undoing the misconfiguration. To simplify this task, we propose Ocasta to automatically determine which files contain configuration state. Ocasta uses a novel {\em similarity} metric to measures how similar a file's versions are to each other, and a set of filters to eliminate non-persistent files from consideration. These two mechanisms enable Ocasta to identify all 72 configuration files out of 2363 versioned files from 6 common applications in two user traces, while mistaking only 33 non-configuration files as configuration files. Ocasta allows a versioning file system to eliminate roughly 66\% of non-configuration file versions from its logs, thus reducing the number of file versions that a user must manually examine to recover from a misconfiguration.

Systems can become misconfigured for a variety of reasons such as operator errors or buggy patches. When a misconfiguration is discovered, usually the first order of business is to restore availability, often by undoing the misconfiguration. To simplify this task, we propose Ocasta to automatically determine which files contain configuration state. Ocasta uses a novel {\em similarity} metric to measures how similar a file's versions are to each other, and a set of filters to eliminate non-persistent files from consideration. These two mechanisms enable Ocasta to identify all 72 configuration files out of 2363 versioned files from 6 common applications in two user traces, while mistaking only 33 non-configuration files as configuration files. Ocasta allows a versioning file system to eliminate roughly 66\% of non-configuration file versions from its logs, thus reducing the number of file versions that a user must manually examine to recover from a misconfiguration.

Configuration files are a vital part of any server setup. Knowing what configuration files have been manipulated is vital in knowing what services are running and how they are configured on a system. Changes made to these configuration files must be manually documented or collected using some automated documentation tool. Both these methods rely on being implemented early for the changes to be sufficiently documented. If a system didn’t implement these methods of documentation then there is no absolute way of knowing what changes have been made to that system without doing a manual search through potentially hundreds of files to find changes. Finding all changes made to a system lacking documentation is a time-consuming and arduous task. What if the search for changes could be automated once the documentation is long overdue? This thesis aims to create an implementation that finds changes made to configuration files on a Debian system as well as Linux distributions based on Debian such as Ubuntu. The resulting implementation created is called Doc-Overdue. Doc-Overdue consists of a script written in Python and utilizes the Debian Package Management System to find reference files to compare to the configuration files on the system. The script also runs tests to aid in finding new and/or modified configuration files without a reference file available. The results are presented in a formatted comprehensive report automatically created by Doc-Overdue. The report will include change reports created by the Diff-utility that makes it easy to find exactly what changes have been made to each changed configuration file. This approach finds changes made to systems without the need for any prior documentation of the system. The implementation was tested with a custom-made script that made modifications to configuration files for Doc-Overdue to find. The test showed Doc-Overdue to have an accuracy of 87.5% in finding changed configuration files on the system. This result shows that this approach for finding configuration file changes has a lot of promise. The thesis ends with a discussion and a list of potential future work that could hopefully lead to further improvements in the field of configuration detection.

The aim of this study is to investigate if there is a way a computer can accurately and automatically react on altered configuration file(s) with a minimum of resource utilization and by what means the developer(s) of an application can perform a check of the altered configuration file for their application. In a typical GNU/Linux installation the configuration files are literally counted by the thousands, monitoring these files is a task that for the most part exceeds any system administrator's abilities. Each file has its own syntax that needs to be known by the administrator. Either one of these two tasks could give any system administrator nightmares concerning the difficulty level especially when both tasks are combined. The system administrator could attempt to automate the monitoring tasks together with the syntax checking. There are some tools in the repositories of each distribution for monitoring files but none that lets one monitor and take (predefined or user defined) actions based on what the file monitor reports, the type of file and its contents. A complete tool is not presented in this study, merely a proof of concept that monitoring and taking actions especially with version 2.6.13 (or newer) kernel of GNU/Linux with plugins are quite possible with relatively small computer resource. During this study some questions arose that are worth taking into consideration when a complete monitoring tool is to be developed, amongst others they are: add a trusted user, add both textual and graphical user interface, monitor more than one file path. This study was performed on GNU/Linux CentOS 6 distribution, all programming was done in BASH with an effort to minimize used/installed programs.

This master thesis focuses on the issue of automation of virtual infrastructure and available tools such as Ansible, Terraform and Puppet. The individual tools are compared here in sequence for installations or configuration creation. The result of this semester thesis is the selection of a suitable tool for automation of virtual infrastructure.

Master thesis Testing of Directional Earth Fault Protections Using the Experimentally Obtained Fault Records deals with the protective functions of earth fault protections during earth faults in compensated medium voltage distribution network and their testing options. At the beginning of the thesis we charakterize operation of medium voltage distribution system in general. We begin with definition and characteristics of earth fault and its compartmentalization by the type of the fault, size of the transition resistance and duration. We also mention grounding methods of node winding transformer on medium voltage distribution network and we describe the most common of them in detail, i.e. network grouded through the arc suppression coil and its operation with automatic switching auxiliary resistor. In this part of the thesis we discuss the localization of the earth fault using passive static methods in compensated systems, which include wattmetric, admittance and conductance method. In next section we deal with the fault records stored in COMTRADE file format, its structure and all elements of its configuration and data file. We create and describe an example of converting ADF file format, recorded by Yokogawa oscilloscope fault recorder, into COMTRADE file format using Microsoft Excel program and M-File created in the MATLAB program. In the practical part we introduce workspace devices and software, which includes secondary testing equipment OMICRON CMC 256plus and its software OMICRON Test Universe with Advance Transplay test module, we further describe multifunctional earth fault protection RYo from PROTECTION & CONSULTING, s. r. o. and machine terminal REM 543 from ABB and their protective functions. The last part describes the actual testing of parallel connected earth fault protection with COMTRADE fault records by Advance Transplay test module in the OMICRON Test Universe. In the conclusion we describe evaluation of the suitability of each protective functions of earth fault protection in a variety of sizes the transition resistance at the earth fault location.

The objective of this thesis was to study problems of an insufficient database processing performance and possibilities how to improve the performance with database configuration file optimizations, more powerful hardware and parallel processing. The master thesis contains a description of relational databases, storage media and different forms of parallelism with its use in database systems. There is a description of the developed software for testing database performance. The program was used for testing several database configuration files, various hardware, different database systems (PostgreSQL, Oracle) and advantages of parallel method "partitioning". Test reports and evaluation results are described at the end of the thesis.