[{"data":1,"prerenderedAt":-1},["ShallowReactive",2],{"detail-sidebar-cat-1-en-105":3,"doc-seo-240347-105":53,"doc-detail-240347-en":126},{"code":4,"msg":5,"data":6},0,"success",[7,14,19,24,29,34,39,44,49],{"id":8,"doc_module":9,"doc_module_name":10,"category_name":11,"show_sort_weight":12,"slug":13},11,1,"Template","Presentations",90,"presentations",{"id":15,"doc_module":9,"doc_module_name":10,"category_name":16,"show_sort_weight":17,"slug":18},12,"Resumes",80,"resumes",{"id":20,"doc_module":9,"doc_module_name":10,"category_name":21,"show_sort_weight":22,"slug":23},14,"Invoices",70,"invoices",{"id":25,"doc_module":9,"doc_module_name":10,"category_name":26,"show_sort_weight":27,"slug":28},15,"Posters",60,"posters",{"id":30,"doc_module":9,"doc_module_name":10,"category_name":31,"show_sort_weight":32,"slug":33},16,"Social Media",50,"social-media",{"id":35,"doc_module":9,"doc_module_name":10,"category_name":36,"show_sort_weight":37,"slug":38},17,"Forms",40,"forms",{"id":40,"doc_module":9,"doc_module_name":10,"category_name":41,"show_sort_weight":42,"slug":43},18,"Letters",30,"letters",{"id":45,"doc_module":9,"doc_module_name":10,"category_name":46,"show_sort_weight":47,"slug":48},21,"Paper Templates",5,"papers-templates",{"id":50,"doc_module":9,"doc_module_name":10,"category_name":51,"show_sort_weight":4,"slug":52},158,"General","general-158",{"code":4,"msg":54,"data":55},"ok",{"site_id":56,"language":57,"slug":58,"title":59,"keywords":60,"description":61,"schema_data":62,"social_meta":119,"head_meta":121,"extra_data":123,"updated_unix":125},105,"en","failure-of-ems-due-to-over-utilization-of-disk-storage","Failure of EMS Due to Over Utilization of Disk Storage","","Appendix D lesson learned documents a reliability failure in an EMS/SCADA environment caused by excessive hard disk storage utilization on the SCADA server. Engineers found the control application lost functionality because the disk was fully utilized, leaving operators with visibility but no control. Investigation traced the issue to an automatic file purge process that did not work correctly, allowing storage to exceed maximum capacity. Corrective measures include fixing the purge process, upgrading SCADA hardware with additional disk capacity, and adding hard disk utilization monitoring to periodic performance monitoring.",{"@graph":63,"@context":118},[64,80,101],{"@type":65,"itemListElement":66},"BreadcrumbList",[67,71,74,77],{"item":68,"name":69,"@type":70,"position":9},"https://docshare.wps.com","Home","ListItem",{"item":72,"name":10,"@type":70,"position":73},"https://docshare.wps.com/template/",2,{"item":75,"name":51,"@type":70,"position":76},"https://docshare.wps.com/template/general/",3,{"item":78,"name":59,"@type":70,"position":79},"https://docshare.wps.com/template/failure-of-ems-due-to-over-utilization-of-disk-storage/240347/",4,{"url":78,"name":59,"@type":81,"image":82,"author":87,"headline":59,"publisher":90,"fileFormat":93,"inLanguage":57,"description":61,"dateModified":94,"datePublished":95,"encodingFormat":93,"isAccessibleForFree":96,"interactionStatistic":97},"DigitalDocument",{"url":83,"@type":84,"width":85,"height":86},"https://docshare.wps.com/thumbnails/failure-of-ems-due-to-over-utilization-of-disk-storage/240347.png","ImageObject",442,249,{"name":88,"@type":89},"Lucas Vance","Person",{"url":68,"name":91,"@type":92},"DocShare","Organization","application/pdf","2026-09-20","2026-09-11",true,{"@type":98,"interactionType":99,"userInteractionCount":73},"InteractionCounter",{"@type":100},"ViewAction",{"@type":102,"mainEntity":103},"FAQPage",[104,110,114],{"name":105,"@type":106,"acceptedAnswer":107},"What caused the EMS/SCADA failure described in the lesson learned?","Question",{"text":108,"@type":109},"Hard disk storage on the SCADA server was fully utilized, which prevented the control application from functioning properly.","Answer",{"name":111,"@type":106,"acceptedAnswer":112},"How did the file purge issue contribute to the problem?",{"text":113,"@type":109},"An automatic file purge process was not functioning correctly, allowing the hard disk to exceed its maximum capacity.",{"name":115,"@type":106,"acceptedAnswer":116},"What corrective actions were taken to prevent recurrence?",{"text":117,"@type":109},"The file purge process was corrected, SCADA hardware was upgraded with additional disk storage, and hard disk utilization monitoring was added to periodic performance monitoring.","https://schema.org",{"og:url":78,"og:type":120,"og:title":59,"og:site_name":91,"og:description":61},"article",{"robots":122,"canonical":78},"index,follow",{"doc_id":124,"site_id":56},240347,1789160264,{"code":4,"msg":5,"data":127},{"doc_id":124,"user_id":128,"nickname":88,"user_avatar":129,"doc_module":9,"category_id":50,"category_name":51,"doc_title":59,"doc_description":61,"doc_content":130,"file_id":131,"file_url":132,"file_type":133,"file_size":134,"view_count":73,"is_deleted":4,"is_public":9,"is_downloadable":9,"audit_status":9,"page_count":73,"language":135,"language_code":57,"site_id":56,"html_lang":57,"table_of_contents":136,"faqs":137,"seo_title":138,"seo_description":61,"update_tm":125,"read_time":9},549768064622,"https://ap-avatar.wpscdn.com/davatar_6f874abed73319feea01a86fa6f0fab8","Appendix D  \nLesson Learned Template  \nTitle: Failure of EMS Due to Over Utilization of  \n Disk Storage  \nPrimary Interest Groups  \nReliability Coordinators Transmission Operators  \nTransmission Operators  \nProblem Statement  \nLoss of control functionality due to the hard disk on the SCADA server being been fully utilized..  \nDetails  \nEngineers identified that the hard disk on the SCADA server was fully utilized which prevented the control application from functioning properly. Operators had visibility of the system, but did not have control. The post event investigation identified that an automatic file purge process was not functioning correctly which caused the hard disk to exceed its maximum capacity.  \nCorrective Actions  \nThe following actions were taken to correct the problem.  \n• The file purge process was corrected.  \n• SCADA hardware was upgraded to include an additional amount of disk storage.  \n• Hard disk utilization monitoring is now included with the periodic performance monitoring of the  \nsystem.  \nLesson Learned  \nSCADA equipment monitoring should include monitoring of hard disk storage utilization and the functionality of purging process where applicable.  \nFor more information please contact:  \nEarl Shockley  \nDirector of Event Analysis and Investigations  \nJohn Mosier  \nAssistant Vice President-System Operations  \n[earl.shockley@nerc.net](earl.shockley@nerc.net) [jmosier@npcc.org](jmosier@npcc.org)  \n404-446-2560 212-840-1070  \nSource of Lesson Learned:  \nThis document is designed to convey lessons learned from NERC’s various activities. It is not intended to establish new requirements under NERC’s Reliability Standards or to modify the requirements in any existing reliability standards. Compliance will continue to be determined based on language in the NERC Reliability Standards as they may be amended from time to time. Implementation of this lesson learned isnot a substitute for compliance with requirements in NERC’s Reliability Standards.","cbCaioEOBjzcqZUm","https://ap.wps.com/l/cbCaioEOBjzcqZUm","pdf",409565,"English","# Lesson Learned Template\n## Title\n## Primary Interest Groups\n## Problem Statement\n## Details\n## Corrective Actions\n## Lesson Learned\n## Contacts","[{\"question\":\"What caused the EMS/SCADA failure described in the lesson learned?\",\"answer\":\"Hard disk storage on the SCADA server was fully utilized, which prevented the control application from functioning properly.\"},{\"question\":\"How did the file purge issue contribute to the problem?\",\"answer\":\"An automatic file purge process was not functioning correctly, allowing the hard disk to exceed its maximum capacity.\"},{\"question\":\"What corrective actions were taken to prevent recurrence?\",\"answer\":\"The file purge process was corrected, SCADA hardware was upgraded with additional disk storage, and hard disk utilization monitoring was added to periodic performance monitoring.\"}]","Failure of EMS Due to Over Utilization of Disk Storage | PDF"]