{"id":9163,"date":"2021-06-28T13:37:55","date_gmt":"2021-06-28T11:37:55","guid":{"rendered":"https:\/\/blog.rwth-aachen.de\/itc\/?p=9163"},"modified":"2023-05-17T10:54:33","modified_gmt":"2023-05-17T08:54:33","slug":"moodletrouble%c2%b2","status":"publish","type":"post","link":"https:\/\/blog.rwth-aachen.de\/itc\/en\/2021\/06\/28\/moodletrouble%c2%b2\/","title":{"rendered":"#moodletrouble\u00b2 &#8211; The chronology of a malfunction"},"content":{"rendered":"<div class=\"twoclick_social_bookmarks_post_9163 social_share_privacy clearfix 1.6.4 locale-en_US sprite-en_US\"><\/div><div class=\"twoclick-js\"><script type=\"text\/javascript\">\/* <![CDATA[ *\/\njQuery(document).ready(function($){if($('.twoclick_social_bookmarks_post_9163')){$('.twoclick_social_bookmarks_post_9163').socialSharePrivacy({\"txt_help\":\"Wenn Sie diese Felder durch einen Klick aktivieren, werden Informationen an Facebook, Twitter, Flattr, Xing, t3n, LinkedIn, Pinterest oder Google eventuell ins Ausland \\u00fcbertragen und unter Umst\\u00e4nden auch dort gespeichert. N\\u00e4heres erfahren Sie durch einen Klick auf das <em>i<\\\/em>.\",\"settings_perma\":\"Dauerhaft aktivieren und Daten\\u00fcber-tragung zustimmen:\",\"info_link\":\"http:\\\/\\\/www.heise.de\\\/ct\\\/artikel\\\/2-Klicks-fuer-mehr-Datenschutz-1333879.html\",\"uri\":\"https:\\\/\\\/blog.rwth-aachen.de\\\/itc\\\/en\\\/2021\\\/06\\\/28\\\/moodletrouble%c2%b2\\\/\",\"post_id\":9163,\"post_title_referrer_track\":\"%23moodletrouble%C2%B2+%26%238211%3B+The+chronology+of+a+malfunction\",\"display_infobox\":\"on\"});}});\n\/* ]]> *\/<\/script><\/div><p><div id=\"attachment_9164\" style=\"width: 340px\" class=\"wp-caption alignright\"><img loading=\"lazy\" decoding=\"async\" aria-describedby=\"caption-attachment-9164\" class=\"wp-image-9164\" src=\"https:\/\/blog.rwth-aachen.de\/itc\/files\/2021\/06\/Stoerung-300x188.png\" alt=\"Malfunction picture\" width=\"330\" height=\"206\" srcset=\"https:\/\/blog.rwth-aachen.de\/itc\/files\/2021\/06\/Stoerung-300x188.png 300w, https:\/\/blog.rwth-aachen.de\/itc\/files\/2021\/06\/Stoerung.png 640w\" sizes=\"auto, (max-width: 330px) 100vw, 330px\" \/><p id=\"caption-attachment-9164\" class=\"wp-caption-text\">Source: <a href=\" https:\/\/pixabay.com\/images\/id-152459\/\">Pixabay<\/a><\/p><\/div><\/p>\n<p>As some of you may have noticed, <a href=\"https:\/\/moodle.rwth-aachen.de\/\">RWTHmoodle <\/a>was unavailable to RWTH Aachen University employees and students for a total of two days in the second week of June 2021. As we already reported on our channels during the malfunction, a serious database error was the cause. We would like to take this opportunity to briefly explain how this error occurred.<!--more--><\/p>\n<h4>What happened?<\/h4>\n<p>In the morning of the first day (14.06.2021) of the malfunction, a major change of data took place on the database cluster of RWTHmoodle. Usually, this is a normal process. In the case, however, this was rejected by the system due to its size. This is also a normal process, which is primarily intended to ensure the security and integrity of the databases. The rejection of the changes nevertheless led to far-reaching restrictions in the operation of the database cluster. Of five nodes that are normally available, two failed. This ultimately led to the cluster operating with only three for about 30 minutes. All attempts by colleagues from the specialist department, who were already working flat out at the time to solve the problem, to reintegrate the two failed nodes into the cluster were unsuccessful up to that point.<\/p>\n<p>Finally, the manufacturer&#8217;s technical support was contacted and a Prio 1 ticket was opened in order not to lose any more time. In the meantime, access to RWTHmoodle was blocked for users in order to prevent data loss.<\/p>\n<p>First analyses of the manufacturer support pointed to known bugs in the current MySQL version, which is used on the cluster. However, since the possible solutions offered by the manufacturer&#8217;s employees did not lead to success, it was decided during the second day of the malfunction (15.06.2021) to stop the entire database cluster, delete it completely and set it up again. This was successfully accomplished during the course of the day, so that the\u00a0cluster and RWTHmoodle were completely functional and usable again on the morning of the third day (16.06.2021). At this point, it should be mentioned that a data loss could be avoided and that the imported backup had the status of the evening of the first day.<\/p>\n<h4>Findings and measures<\/h4>\n<p>Based on the initial findings obtained during the incident together with the manufacturer, adjustments were made to the operating mode of the database cluster in order to prevent the occurrence of the aforementioned bugs in the future. The bugs themselves are to be fixed by the manufacturer in one of the future MySQL versions. Of course, these would then be extensively tested by our specialist department and a return to the previous operating mode would be examined.<\/p>\n<p>In addition, various concepts are currently being evaluated in order to be able to avoid this and similar problems in principle in the future.<\/p>\n<p>However, since disruptions can never be ruled out, we ask you to contact the <a href=\"https:\/\/help.itc.rwth-aachen.de\/service\/b734502cd73e4201b1f763a65a61bf9c\/article\/093e53465d484c098f3d335b58d38578\/\">IT-ServiceDesk <\/a>in urgent cases.<\/p>\n<p>&nbsp;<\/p>\n<p>Responsible for the content of this article is <a href=\"https:\/\/www.itc.rwth-aachen.de\/cms\/IT-Center\/IT-Center\/Team\/~epvp\/Mitarbeiter-CAMPUS-\/?gguid=0x9356740536A0D54BAE2FFB25A85C91DA&amp;allou=1&amp;lidx=1\">Anastasios Krikas<\/a>.<\/p>","protected":false},"excerpt":{"rendered":"<p>Sorry, this entry is only available in Deutsch.<\/p>\n","protected":false},"author":1859,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"c2c_always_allow_admin_comments":false,"footnotes":""},"categories":[306,315,310],"tags":[96,89,87,95],"class_list":["post-9163","post","type-post","status-publish","format-standard","hentry","category-ankuendigungen","category-services-support","category-studium-lehre","tag-moodletrouble","tag-moodle","tag-rwthmoodle","tag-stoerung"],"aioseo_notices":[],"_links":{"self":[{"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/posts\/9163","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/users\/1859"}],"replies":[{"embeddable":true,"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/comments?post=9163"}],"version-history":[{"count":5,"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/posts\/9163\/revisions"}],"predecessor-version":[{"id":15586,"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/posts\/9163\/revisions\/15586"}],"wp:attachment":[{"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/media?parent=9163"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/categories?post=9163"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/blog.rwth-aachen.de\/itc\/en\/wp-json\/wp\/v2\/tags?post=9163"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}