This bachelor thesis evaluates the impact of datanode crashes on the performance of the read operations of a Hadoop Distributed File System, HDFS. The goal is to better understand how datanode crashes, as well as how certain parameters, affect the  performance of the read operation by looking at the execution time of the get command. The parameters used are the number of crashed nodes, block size and file size. By setting up a Linux test environment with ten virtual machines and Hadoop installed on them and running tests on it, data has been collected in order to answer these questions. From this data the average execution time and standard deviation of the get command was calculated. The network activity during the tests was also measured. The results showed that neither the number of crashed nodes nor block size had any significant effect on the execution time. It also demonstrated that the execution time of the get command was not directly proportional to the size of the fetched file. The execution time was up to 4.5 times as long when the file size was four times as large. A four times larger file did sometimes result in more than a four times as long execution time. Although, the consequences of a datanode crash while fetching a small file appear to be much greater than with a large file. The average execution time increased by up to 36% when a large file was fetched but it increased by as much as 85% when fetching a small file.

In the diploma thesis "Cooperation of Fire Rescue Brigade of Central Bohemia Region and Voluntary Fire Brigade Corps Units of Municipalities with Predestination for Traffic Accident Interventions", the author dealt with the evaluation of possibilities of cooperation in traffic accidents between fire brigade units of Central Bohemia and voluntary fire brigade units of municipalities destined for rescue and liquidation accidents. In the theoretical part of the thesis there are given the basic terms from the area of rescue of injured persons from crashed vehicles, legal and internal regulations dealing with this issue and criteria for fulfillment of predetermination for rescue work in traffic accidents - professional training, numbers and equipment with mobile fire equipment and material means fire protection for rescue. The next chapter in the theoretical part is the concrete activities of fire protection units in the type of traffic accident. The conclusion of the theoretical part consists of the existing situation in the Central Bohemian Region - description of transport infrastructure, area coverage of the region by fire protection units destined for rescue work in traffic accidents and statistics of accident rate on roads for 2018, in which the fire brigade of the Central Bohemia Region and units of voluntary fire brigade units of municipalities intervened predestined for rescue work in traffic accidents. The practical part presents the results of the questionnaire survey. For this questionnaire survey, the first representative sample of the survey was selected by the commanders of voluntary fire brigade units of municipalities of the Central Bohemian Region destined for rescue operations in traffic accidents. The second representative sample of the survey was selected by guarantors for individual territorial departments of the Central Bohemian Fire Rescue Service for rescue together with instructors for rescuing injured persons in road accidents at individual stations of the Fire Rescue Service of the Central Bohemia Region. The survey was carried out for a defined set in the form of a semi-structured questionnaire. Individual questionnaires were evaluated on the basis of the survey in Chapter 3. Discussion. This evaluation found that no one is a clear opponent of volunteer fire brigade units in municipalities destined for rescue operations in traffic accidents and their traffic accidents are desirable, but there is still plenty of room for improvement. As a measure to increase the efficiency of cooperation between the fire brigade units of the Central Bohemian Region by voluntary fire brigade units of municipalities with a predestination for rescue work in traffic accidents, it was recommended to newly determine the units of voluntary fire brigades of municipalities for rescue work in road accidents in the Central Bohemian Region where unit of Fire Rescue Brigade of Central Bohemia Region has a long range. Furthermore, it was recommended to create internal regulations regulating the minimum equipment of mobile fire fighting equipment and material fire protection equipment for rescue of volunteer fire brigade units of municipalities destined for rescue work in traffic accidents and to develop a new internal regulation regulating the requirements of training fire brigade units as they are confusing.